6 These passages are for the Jews, and for these of our own brethren. Why so? Because these Scriptures of the Old Testament both the Jews receive, and these our brethren receive. But Christ Himself, whom the others do not receive, let us see if these last receive. Let Him speak Himself, speak both for Himself who is the Head, and for His Body which is the Church; for so in us the head speaks for the body. Hear for the Head; He was risen from the dead, He found the disciples hesitating, doubting, not believing for joy; He “opened their understanding that they might understand the Scriptures, and said to them, Thus it is written, and thus it behooved Christ to suffer, and to rise again from the dead the third day.”
Thus for the Head; let Him speak for the Body too; “And that repentance and remission of sins should be preached in His Name throughout all nations, beginning at Jerusalem.” Let the Church then speak to her enemies, let her speak. She does speak clearly, she is not silent: only let them give ear. Brethren, you have heard the testimonies, now acknowledge me. “Search the Scriptures, in which you hope you have eternal life: they testify of me.” What I have said is not of my own, but of my Lord's; and notwithstanding, you still turn away, still turn your backs.
“How can you believe me, who look for glory one from another, and seek not the glory which is of God only? For being ignorant of God's righteousness, you have a zeal of God, but not according to knowledge. For being ignorant of God's righteousness, and wishing to establish your own, you have not submitted yourselves to the righteousness of God.” What else is it to be ignorant of God's righteousness, and to wish to establish your own, but to say, “It is I who sanctify, it is I who justify; what I may have given is holy”? Leave to God what is God's; recognise, O man, what is man's. You are ignorant of God's righteousness, and wishest to establish your own. You wish to justify me; it is enough for you that you be justified with me.
Source: Sermons on Selected Lessons of the New Testament (New Advent)