Because Allah the Exalted has said: O you who have believed, do not invalidate your charities with reminders or injury, as does one who spends his wealth to be seen by the people and does not believe in Allah and the Last Day, (up to) Allah's statement: "And Allah does not guide the disbelieving people." Ibn Abbas (may Allah be pleased with them both) said that in the (Noble Quran), the word «صلدا‏» refers to something smooth and slippery. Ikrimah (may Allah be pleased with him) said that in the (Noble Quran), the word «وابل‏» refers to heavy rain, and the word «الطل» refers to dew.

Because Allah, the Exalted, has said: "Kind speech and forgiveness of (the poor man's) harsh words are better than charity followed by injury (to the one to whom charity is given), for Allah is Most Rich, Most Forbearing."

Because Allah the Exalted has said that Allah diminishes usury and increases charity, and Allah does not like any ungrateful sinner. Those who believed and did righteous deeds, established prayer, and gave zakat—their reward is with their Lord, and there will be no fear upon them, nor will they grieve.

Narrated Abu Huraira: Allah's Apostle said, "If one give in charity what equals one date-fruit from the honestly earned money and Allah accepts only the honestly earned money --Allah takes it in His right (hand) and then enlarges its reward for that person (who has given it), as anyone of you brings up his baby horse, so much s that it becomes as big as a mountain

Narrated Haritha bin Wahab: I heard the Prophet saying, "O people! Give in charity as a time will come upon you when a person will wander about with his object of charity and will not find anybody to accept it, and one (who will be requested to take it) will say, "If you had brought it yesterday, would have taken it, but today I am not in need of it."

Narrated Abu Huraira: The Prophet said, "The Hour (Day of Judgment) will not be established till your wealth increases so much so that one will be worried, for no one will accept his Zakat and the person to whom he will give it will reply, 'I am not in need of it.' "

Narrated `Adi bin Hatim: While I was sitting with Allah's Apostle (p.b.u.h) two person came to him; one of them complained about his poverty and the other complained about the prevalence of robberies. Allah's Apostle said, "As regards stealing and robberies, there will shortly come a time when a caravan will go to Mecca (from Medina) without any guard. And regarding poverty, The Hour (Day of Judgment) will not be established till one of you wanders about with his object of charity and will not find anybody to accept it And (no doubt) each one of you will stand in front of Allah and there will be neither a curtain nor an interpreter between him and Allah, and Allah will ask him, 'Did not I give you wealth?' He will reply in the affirmative. Allah will further ask, 'Didn't send a messenger to you?' And again that person will reply in the affirmative Then he will look to his right and he will see nothing but Hell-fire, and then he will look to his left and will see nothing but Hell-fire. And so, any (each one) of you should save himself from the fire even by giving half of a date-fruit (in charity). And if you do not find a hall datefruit, then (you can do it through saying) a good pleasant word (to your brethren). (See Hadith No. 793 Vol. 4).

Narrated Abu Musa: Thy Prophet (p.b.u.h) said, "A time will come upon the people when a person will wander about with gold as Zakat and will not find anybody to accept it, and one man will be seen followed by forty women to be their guardian because of scarcity of men and great number of women. "

And (in the Noble Qur’an is) «ومثل الذين ينفقون أموالهم» the example of those who spend their wealth, (to) the statement of the Lord «من كل الثمرات‏» up to.

Narrated Abu Mas`ud: When the verses of charity were revealed, we used to work as porters. A man came and distributed objects of charity in abundance. And they (the people) said, "He is showing off." And another man came and gave a Sa (a small measure of food grains); they said, "Allah is not in need of this small amount of charity." And then the Divine Inspiration came: "Those who criticize such of the believers who give in charity voluntarily and those who could not find to give in charity except what is available to them." (9.79).