Zakat ut-Tatawwu or Voluntary Sadaqah:
Islam calls upon the individual to spend freely in ways that please the heart of the donor, and evoke generosity, goodness, reverence, and obedience to Allah:

Zakat ut-Tatawwu or Voluntary Sadaqah in the Qur'an:
Allah, the Exalted One, says: "The parable of those who spend their wealth in the way of Allah is that of a grain of corn: it grows seven ears, and each ear has a hundred grains. Allah gives manifold increase to whom He pleases; Allah cares for all and knows all things" [al-Baqarah 261].

 "By no means shall you attain righteousness unless you give freely of that which you love, and whatever you give, Allah knows it well" [al'Imran 92].

 "And spend from what We have made you heir. For those of you who believe and spend, for them is a great reward" [alHadid 7].

Zakat ut-Tatawwu or Voluntary Sadaqah in the Hadith:
The Messenger of Allah, upon whom be peace, said: "Sadaqah appeases the anger of the Lord and wards off the agony of death."

 It is similarly related that the Messenger of Allah, upon whom be peace, said: "The sadaqah of the Muslim increases during his lifetime. It also softens the agony of death, and through it, Allah takes away arrogance and vanity."

 The Messenger of Allah, upon whom be peace, said: "There is not a day in which the obedient servants rise in the morning or two angels descend, and one of them says: 'O Allah! Compensate the one who spends freely.' The other angel says: 'O Allah! Let an annihilation come upon the one who is niggardly.' " This is related by Muslim.

 The Messenger of Allah, upon whom be peace, said: "Acts of kindness protect one from ruin wrought by evil. Sadaqah given secretly appeases the anger of the Lord, and a gift to strengthen the ties of relationship increases one's life span. All good deeds are sadaqah, and those who do acts of kindness in this world are also the same people in the other world. Those who do misdeeds in this world are the same people in the other world. The first of those who shall enter Paradise are the people who do acts of kindness." This is related by at-Tabarani in al'Awsat. Mandhiri does not mention it.

Types of Sadaqah:
Sadaqah is not restricted to any special deed of righteousness. The general rule is that all good deeds are sadaqah. Some of them are as follows:

 The Messenger of Allah, upon whom be peace, said: "Every Muslim has to give sadaqah." The people asked: "O Prophet of Allah, what about the one who has nothing?" He said: "He should work with his hands to give sadaqah." They asked: "If he cannot find [work]?" He replied: "He should help the needy who asks for help." They asked: "If he cannot do that?" He replied: "He should then do good deeds and shun evil, for this will be taken as sadaqah." This is related by al-Bukhari and others.

 The Messenger of Allah, upon whom be peace, said: "Sadaqah is prescribed for every person every day the sun rises. To administer justice between two people is sadaqah. To assist a man upon his mount so that he may ride it is sadaqah. To place his luggage on the animal is sadaqah. To remove harm from the road is sadaqah. A good word is sadaqah. Each step taken toward prayer is sadaqah." This is related by Ahmad and others.

 Abu Dhar al-Ghafari said: "The Messenger of Allah, upon whom be peace, said: 'Sadaqah is for every person every day the sun rises.' I said: 'O Messenger of Allah, upon whom be peace, from what do we give sadaqah if we do not possess property?' He said: 'The doors of sadaqah are takbir [i.e., to say: Allahu-akbar, Allah is Great]; Subhan-Allah [Allah is free from imperfection]; Alhamdulillah [all praise is for Allah]; La -ilaha-illallah [there is no god other than Allah]; Astaghfirul-lah [I seek forgiveness from Allah]; enjoining good; forbidding evil; removing thorns, bones, and stones from the paths of people; guiding the blind; listening to the deaf and dumb until you understand them; guiding a person to his object of need if you know where it is; hurrying with the strength of your legs to one in sorrow who is appealing for help; and supporting the weak with the strength of your arms. These are all the doors of sadaqah. [The sadaqah] from you is prescribed for you, and there is a reward for you [even] in sex with your wife.' " This is related by Ahmad, and the wording is his. According to Muslim, they said: "O Messenger of Allah, upon whom be peace, is there a reward if one satisfies his passion?" He said: "Do you know that if he satisfies it unlawfully he has taken a sin upon himself? Likewise, if he satisfies it lawfully, he is rewarded."

 It is related following Abu Dhar that the Messenger of Allah, upon whom be peace, said: "Sadaqah is prescribed for each descendant of Adam every day the sun rises." It was asked: "O Messenger of Allah, upon whom be peace, from what do we give sadaqah every day?" He said: "The doors of goodness are many--the tasbih [to say 'Subhaan-Allah'], the tamhid [to say 'Alhamdu lillah'], the tahlil [to say 'La-ilaha-illallah], enjoining good, forbidding evil, removing harm from the road, listening to the deaf, leading the blind, guiding one to the object of his need, hurrying with the strength of one's legs to one in sorrow who is asking for help, and supporting the feeble with the strength of one's arms--all of these are sadaqah prescribed for you." This is related by Ibn Hibban in his Sahih. Al-Bukhari related it in a shortened form and added in his report: "Your smile for your brother is sadaqah. Your removal of stones, thorns, or bones from the paths of people is sadaqah. Your guidance of a person who is lost is sadaqah."

 The Messenger of Allah also said: "He from among you who is able to protect himself from the Fire should give sadaqah, even if but with half a date. If he does not find it, then with a good word."

 The Messenger of Allah, upon whom be peace, said: "Allah, the Majestic and Mighty, shall say on the Day of Judgment: 'O son of man! I was ill and you did not visit me.' He will reply: 'O my Lord! How could I visit You and You are the Lord of the Worlds?' Allah shall say: 'Did you not know that My slave, so-and-so, was ill and you did not visit him? If you had visited him, you would have found Me with him. O son of man! I asked you for food and you did not give it to me.' He will reply: 'O my Lord! How could I give You food--You are the Lord of the Worlds?' Allah shall say: 'Did you not know that My slave, so-and-so, asked you for food and you did not give it to him? Did you not know that if you had given the food, you would have found that with Me? O son of man! I asked you to quench My thirst and you did not.' He will say: 'O my Lord! How could I quench Your thirst--You are the Lord of the Worlds?' Allah shall say: 'My slave, so-and-so, asked you to quench his thirst and you did not. If you had given him to drink, you would have found that with Me.' " This is related by Muslim.

 The Messenger of Allah, upon whom be peace, said: "A Muslim does not plant or sow anything from which a person, an animal, or anything eats but it is considered as sadaqah from him." This is related by al-Bukhari.

 The Messenger of Allah, upon whom be peace, said: "Every good deed is sadaqah. To meet your brother with a smiling face and to pour out from your bucket into his container are sadaqah."

Those Who Have Precedence for Receiving Sadaqah:
One's children, family, and relatives have precedence over others. It is not permissible to give sadaqah to a stranger when you and your dependents are in need of it.

 It is related from Jabir that the Messenger of Allah, upon whom be peace, said: "When one of you is poor, he starts with himself. If anything is left, he spends it on his dependents. If anything is (still left) then on his relatives, and then, if more is left, he spends it here and there."

 The Messenger of Allah, upon whom be peace, said: "Give sadaqah." A man said: "I have a dinar." He replied: "Give it to yourself as sadaqah." He said: "I have another dinar." He replied: "Give it to your wife as sadaqah." He said: "I have another dinar." He replied: "Give it to your child as sadaqah." He said: "I have another dinar." He replied: "Give it to your servant as sadaqah." He said: "I have another dinar." He replied: "You would be able to assess better [to whom to give it]." This is related by Abu Dawud, an-Nasa'i, and Hakim. Hakim grades it as authentic.

 The Messenger of Allah, upon whom be peace, said: "A man has sinned enough if he neglects to feed those in need." This is related by Muslim and Abu Dawud.

 Also: "The most excellent sadaqah is that given to a relative who does not like you." This is related by at-Tabarani and Hakim. The latter grades it authentic.

The Invalidation of Sadaqah:
It is unlawful for the one giving sadaqah to remind the recipient of his generosity, to reproach bim, or to make a show with his sadaqah. Allah warns: "O you who believe! Do not invalidate your sadaqah by reminders of your generosity or by injury, like those who spend their property to be seen by men" [al-Baqarah 264].

 The Messenger of Allah, upon whom be peace, said: "There are three [types of people]. Allah shall not speak to them, notice them, or sanctify them; and for them is a grievous penalty." Abu Dhar inquired: "O Messenger of Allah, who are the ones gone wrong and astray?" He replied: "Those who through conceit lengthen their garments to make them hang on the ground, who give nothing without reproach, and who sell their merchandise swearing untruthfully [to its quality]."

Giving What is Unlawful as Sadaqah:
Allah does not accept sadaqah if it is from what is unlawful: The Messenger of Allah, upon whom be peace, said: "O people! Allah is good and accepts only good, and He has instructed the believers through the Messengers. Allah, the Mighty and the Majestic, says: 'O Messengers! Consume what is good and work righteously. I am well-acquainted with what you do' [al-Mu'minum 51]." He also calls upon [you]: 'O you who believe! Consume of the good that We have provided for you' [al-Baqarah 172]. Then [the Messenger] mentioned a man who had traveled for a long time. Unkempt and covered in dust, he raised his hands to the heavens (and cried): 'O my Lord! O my Lord!' His food was unlawful, his drink was unlawful, his clothing was unlawful, and what he had provided to sustain himself with was also unlawful. How could his invocation be accepted?" This is related by Muslim.

 Also: "If one gives a date bought from honestly earned money (and Allah accepts only good), Allah accepts it in His right hand and enlarges [its rewards] for its owner (as one rears his foal) until it becomes as big as a mountain." This is related by al-Bukhari.

Sadaqah of the wife from the property of her husband:
It is permissible for the wife to give sadaqah from her husband's holdings if she knows that he would not mind. However, it is unlawful if she is not sure of this: It is related from 'Aishah that the Messenger of Allah, upon whom be peace, said: "When a wife gives something as sadaqah from the food of her home without causing any waste, she will get the reward for what she has given. Her husband will be rewarded for what he has earned, and the keeper (if any) will be similarly rewarded. The one does not reduce the reward of the other in any way." This is related by al-Bukhari.

 Abu Umamah reports that he had heard the Messenger of Allah, upon whom be peace, saying in a sermon during the year of the Farewell Pilgrimage: "The wife should not spend anything from the household of her husband without his permission." He asked: "O Messenger of Allah, upon whom be peace! Not food either?" He said: "That is the most excellent of our holdings." This is related by at-Tirmidhi who graded it hassan.

 Of small things which she is in the habit of giving, no permission from her husband is called for: It is related from Asma, daughter of Abu Bakr, that she said to the Messenger of Allah, upon whom be peace: "Zubair is a well-off man. A man in need approached me and I gave him sadaqah from my husband's household without his permission." The Messenger of Allah, upon whom be peace, said: "Give what you are in the habit of giving of what is small, and do not store property away, for Allah shall withhold his blessings from you." This is related by Ahmad, al-Bukhari, and Muslim.

Giving all of one's property in sadaqah:
The jurists say that giving all of one's property in sadaqah is permissible provided the donor is fit, earning, and steadfast, not in debt, nor has dependents for whom adequate support from him is obligatory. If he does not fulfil these conditions, then his action is makruh.

 Jabir narrated: "While we were with the Messenger of Allah, upon whom be peace, a man came with what was like an egg of gold. He said: 'O Messenger of Allah! I obtained this from buried treasure, so take it. It is sadaqah, and I do not possess anything other than it.' The Messenger of Allah, upon whom be peace, turned away from him and he [the man] then approached him from the direction of his left side. The Messenger of Allah, upon whom be peace, then turned away from him again and he approached him from behind. Then the Messenger of Allah, upon whom be peace, took it and threw it at him. If it had hit him, it would have injured him. Then he said: 'One of you comes with all his property to make sadaqah, then after [giving all he had] he sits [by the road] begging from the people. Sadaqah is given by the one who is rich.' " This is related by Abu Dawud and Hakim. The latter said: "It is authentic according to the stipulation of Muslim. In its transcription is Muhammad ibn Ishaq."

Giving Sadaqah to the Dhimmi and the Soldier:
One can give sadaqah to the dhimmi and the soldier, and one is rewarded for that. Allah praised a group of people (for this) when He said: "And they feed, for His love, the indigent, orphan, and captive" [ad-Dahr 6]. The captive is a soldier. Allah says: "Allah has not forbidden you with regard to those who have not made war against you on account of [your] faith and have not driven you out of your homes to deal kindly and justly with them; Allah loves those who are just" [al-Mumtahanah 8].

 Asma, the daughter of Abu Bakr, reports: "My mother came to me and she is a polytheist. I said: 'O Messenger of Allah, upon whom be peace! If my mother came to me and she is willing, do I establish a link with her?' He said: 'Yes, establish a link with your mother.' "

Sadaqah on Animals:
The Messenger of Allah, upon whom be peace, is reported to have said: "While a man was walking along a road, he became very thirsty and found a well. He lowered himself into the well, drank, and came out. Then [he saw] a dog protruding its tongue out with thirst. The man said: 'This dog has become exhausted from thirst in the same way as I.' He lowered himself into the well again and filled his shoe with water. Then he took the dog by the mouth until he had raised himself. He gave the dog some water to drink. He thanked Allah, and [his sins were] forgiven." They asked: "O Messenger of Allah, upon whom be peace! Is there a reward for us in our animals?" He said: "There is a reward in every living thing." This is related by al-Bukhari and Muslim.

 The two also related that the Messenger of Allah, upon whom be peace, said: "While a dog was walking around a well, his thirst was near to killing him. One of the prostitutes of the Banu Isra'il saw him. She took off her shoe and drew water for him with it in order to quench his thirst. [For that] she was forgiven [by Allah]."

Perpetual sadaqah:
The perpetual sadaqah (sadaqat ul-jariyah): Ahmad and Muslim relate that the Messenger of Allah, upon whom be peace, said: "When a person dies [the benefit] of his deeds ends, except three: a continuous sadaqah, knowledge from which benefit is derived, or a pious child invoking Allah for him."

Thanking for a Good Deed:
'Abdullah ibn 'Umar reports that the Messenger of Allah, upon whom be peace, said: "Whoever seeks the protection of Allah, give him protection. Whoever asks you in the name of Allah, grant him refuge. Whoever does a good deed to you, reward him and if you do not find anything, invoke Allah on his behalf until you know that he has been rewarded." This is related by Abu Dawud and an-Nasa'i with an authentic chain.

 Ashab ibn Qais reported that the Messenger of Allah, upon whom be peace, is reported to have said: "Whoever does not thank people, does not thank Allah." This is related by Ahmad with a trustworthy chain.

 Usamah ibn Zaid adds that the Messenger of Allah, upon whom be peace, said: "To whom a good deed is done and who says to its doer: 'May Allah reward you with goodness,' also reaps the reward." This is related by at-Tirmidhi.

 Allah is the Most Knowing, and all praise is due to the Lord of the Worlds.