Matthew 12:7

Then, because to the hearers it would seem harsh, He quickly draws a veil over it, giving His discourse, as before, a lenient turn, yet even so expressing Himself with a rebuke. "But if ye had known what this meaneth, I will have mercy and not sacrifice, ye would not have condemned the guiltless." Seest thou how again He inclines His speech to lenity, yet again shows them to be out of the reach of lenity? "For ye would not have condemned," saith He, "the guiltless." Before indeed He inferred the same from what is said of the priests, in the words, "they are guiltless;" but here He states it on His own authority; or rather, this too is out of the law, for He was quoting a prophetic saying.

What I will have mercy, and not sacrifice, signifies, we have explained above. The words, Ye mould never have condemned the innocent, are to be referred to the Apostles, and the meaning is, If ye allow the mercy of Achimelech, in that he refreshed David when in danger of famishing, why do ye condemn My disciples?

The Pharisees, who thought that the key of the kingdom of heaven was in their hands, accused the disciples of doing what was not lawful to do; whereon the Lord reminded them of deeds in which, under the guise of facts, a prophecy was concealed; and that He might show the power of all things, He further added, that it contained the form of that work which was to be, Had ye known what that meaneth, I will have mercy; for the work of our salvation is not in the sacrifice of the Law, but in mercy, and the Law having ceased, we are saved by the mercy of God. Which gift if they had understood they would not have condemned the innocent, that is His Apostles, whom in their jealousy they were to accuse of having transgressed the Law, where the old sacrifices having ceased, the new dispensation of mercy came through them to the aid of all.