The Iron - 57:18 The men and women who give alms, they have given Allah a good debt. They will be repaid in multiples and they deserve a generous reward.
Charity is multiplied in the sight of Allah:
The Cattle/6:160 Whoever brings good, he shall have ten times what he brought. And whoever brings evil, he shall be punished only with its equivalent, and they shall not be wronged.

The Cow/2:265 The example of those who spend their money because they want to earn Allah´s pleasure and they are convinced of it is like the example of a high-yielding garden which yields double its produce when it receives abundant rain, and is content with the dew even if it does not receive abundant rain. Allah sees what you do.
The Cow/2:261 The example of those who spend their money in the Way of Allah is like that of a grain which yields seven ears of grain, one hundred in each. Allah gives in multiples to whomever He wills. Allah is Generous, Knowing.