Catena Aurea on Matthew 7:12: Augustine of Hippo

Otherwise; The Lord had promised that He would give good things to them that ask Him. But that He may own his petitioners, let us also own ours. For they that beg are in every thing, save having of substance, equal to those of whom they beg. What face can you have of making request to your God, when you do not acknowledge your equal? This is said in Proverbs, “Whoso stoppeth his ear to the cry of the poor, he shall cry and shall not be heard.” [Prov 21:13] What we ought to bestow on our neighbour when he asks of us, that we ourselves may be heard of God, we may judge by what we would have others bestow upon us; therefore He says, “All things whatsoever ye would.”