9 “What,” he asks, “what reward shall I give unto the Lord, for all the benefits that He has returned unto me?”. He says not, for all the benefits that He has done unto me but “for all the benefits that He has returned unto me.” What deeds then on the man's part had preceded, that all the benefits of God were not said to be given, but returned? What had preceded, on the man's part, save sins? God therefore repays good for evil, while unto Him men repay evil for good; for such was the return of those who said, “This is the heir: come, let us kill him.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)