Luke 7:19

But how could it come to pass, that Him of whom he said, Behold him who taketh away the sins of the world, he should still not believe to be the Son of God? For either it is presumption to attribute to Christ a divine action ignorantly, or it is unbelief to have doubted concerning the Son of God. But some suppose of John himself that he was indeed so great a prophet as to acknowledge Christ, but still as not a doubting, but pious, prophet disbelieved that He would die, whom he believed was about to come. Not therefore in his faith but in his piety, he doubted; as Peter also, when he said, Be it far from thee, Lord; this shall not be unto thee. (Mat 16:22.)

But we must altogether disallow such an opinion. For no where do we find the Holy Scriptures stating that John the Baptist foretold to those souls in hell the coming of our Saviour. It is also true to say, that the Baptist was not ignorant of the wonderful mystery of the incarnation of the Only-Begotten, and so also along with the other things had known this, that our Lord was about to preach the Gospel to those who were in hell, after He had tasted death for all living as well as dead. But since the word of holy Scripture indeed declared that Christ would come as the Lord and Chief, but the others were sent as servants before Him, therefore was the Lord and Saviour of all called by the prophets, He who cometh, or Who is to come; according to that, Blessed is he who cometh in the name of the Lord; (Ps. 118:26.) and, A little while, and he who is to come shall come, and will not tarry. (Hab. 2:3.) The blessed Baptist therefore, receiving as it were this name from Holy Scripture, sent certain of his disciples to seek whether it was indeed He who cometh, or, Who is to come.

He says not, Art thou He that hast come, but, Art thou he that should come. The sense is, Tell me who am to be slain by Herod, and about to descend into hell, (ad inferna) whether I should announce Thee to the souls below as I have announced Thee to those above? or is this not befitting the Son of God, and Thou art going to send another for these sacraments?

But we have before said, that mystically John was the type of the Law, which was the forerunner of Christ. John then sends his disciples to Christ, that they might obtain the filling up of their knowledge, for Christ is the fulfilling of the Law. And perhaps those disciples are the two nations, of whom the one of the Jews believed, the other of the Gentiles believed because they heard. They wished then to see, because blessed are the eyes that see. But when they shall have come to the Gospel, and found that the blind receive their sight, the lame walk, then shall they say, "We have seen with our eyes," for we seem to ourselves to see Him whom we read of. Or perhaps through the instrumentality (operatrice) of a certain part of our Body a we all seem to have traced out the course of our Lord's passion; for faith comes through the few to the many. The Law then announces that Christ will come, the writings of the Gospel prove that He has come.

But we are then most raised up to Him when we are fallen into straits. John therefore, being cast into prison, takes the opportunity, when his disciples were most in need of Jesus, to send them to Christ. For it follows, And John calling two of his disciples sent them to Jesus, saying, Art thou he that should come, &c.