Midrash Leviticus Rabbah 34:2

Rabbi Pinchas, in the name of Rabbi Reuven, said: "Whoever gives a perutah to a poor person, the Holy One, Blessed be God will give that person life. For indeed, is one really giving only a perutah? No, one gives the poor person life! How can we explain this? If a loaf of bread costs 10 perutot and a poor person standing in the marketplace has only nine, then if someone comes and gives a perutah so that he is able to buy a loaf of bread and, having eaten it, feels refreshed, the Holy One, Blessed be God, says to the donor, 'In your case too, when your soul presses to break loose from your body, I shall return it to you." [Edited for gender neutrality]