3 Thus have we heard the true and good record both of John concerning Christ, and of Christ concerning John. What then is the meaning of this; that John sent his disciples to Him when He was shut up in prison, on the eve of being put to death, and said to them, “Go, say to Him, Are You He that should come, or do we look for another?” Is this then all that praise? That praise is it turned to doubting? What do you say, John? To Whom are you speaking? What do you say?
You speak to your Judge, yourself the herald. You stretched out the finger, and pointed Him out; you said, “Behold the Lamb of God, behold Him who takes away the sins of the world.” Thou said, “Of His fullness have we all received.” Thou said, “I am not worthy to unloose the latchet of His shoes.” And do you now say, “Are You He that should come, or do we look for another?” Is not this the same Christ? And who are you? Are you not His forerunner? Are you not he of whom it was foretold, “Behold, I send my messenger before Your face, who shall prepare Your way before you?” How do you prepare the way, and you are yourself straying from the way?
So then the disciples of John came; and the Lord said to them, “Go, tell John, the blind see, the deaf hear, the lame walk, the lepers are cleansed, the poor have the Gospel preached to them; and blessed is he whosoever shall not be offended in Me.” Do not suspect that John was offended in Christ. And yet his words do sound so; “Are You He that should come?” Ask my works; “The blind see, the deaf hear, the lame walk, the lepers are cleansed, the dead are raised, the poor have the Gospel preached to them;” and do you ask whether I am He?
My works, says He, are My words. “Go, show him again. And as they departed.” Lest haply any one should say, John was good at first, and the Spirit of God forsook him; therefore after their departure, he spoke these words; after their departure whom John had sent, Christ commended John.
Source: Sermons on Selected Lessons of the New Testament (New Advent)