John 1:35-37
The Prophets and Apostles then all preached Him absent; the Prophets before His coming according to the flesh, the Apostles after He was taken up; John alone proclaimed Him present. Wherefore he calls himself the “friend of the Bridegroom”, since he alone was present at the marriage, he it was that did and accomplished all, he made a beginning of the work. And “looking upon Jesus walking, he says, Behold the Lamb of God.” Not by voice alone, but with his eyes also he bore witness to, and expressed his admiration of, Christ, rejoicing and glorying. Nor does he for awhile address any word of exhortation to his followers, but only shows wonder and astonishment at Him who was present, and declares to all the Gift which He came to give, and the manner of purification. For “the Lamb” declares both these things. And he said not, “Who shall take,” or “Who has taken”; but, “Who takes away the sins of the world”; because this He ever does. He took them not then only when He suffered, but from that time even to the present does He take them away, not being repeatedly crucified, (for He offered One Sacrifice for sins,) but by that One continually purging them. As then The Word shows us His pre-eminence, and The Son His superiority in comparison with others, so “The Lamb, The Christ, that Prophet, the True Light, the Good Shepherd,” and whatever other names are applied to Him with the addition of the article, mark a great difference. For there were many “Lambs,” and “Prophets,” and “Christs,” and “sons,” but from all these John separates Him by a wide interval. And this he secured not by the article only, but by the addition of “Only-Begotten”; for He had nothing in common with the creation.
If it seems to any unseasonable that these things should be spoken at “the tenth hour” (that was the time of day, for he says, “It was about the tenth hour”—, such an one seems to me to be much mistaken. In the case indeed of the many, and those who serve the flesh, the season after feasting is not very suitable for any matters of pressing moment, because their hearts are burdened with meats: but here was a man who did not even partake of common food, and who at evening was as sober as we are at morning, (or rather much more so; for often the remains of our evening food that are left within us, fill our souls with imaginations, but he loaded his vessel with none of these things;) he with good reason spoke late in the evening of these matters. Besides, he was tarrying in the wilderness by Jordan, where all came to his baptism with great fear, and caring little at that time for the things of this life; as also they continued with Christ three days, and had nothing to eat. For this is the part of a zealous herald and a careful husbandman, not to desist before he see that the planted seed has got a firm hold. “Why then did he not go about all the parts of Judæa preaching Christ, rather than stand by the river waiting for Him to come, that he might point Him out when He came?” Because he wished that this should be effected by His works; his own object being in the mean time only to make Him known, and to persuade some to hear of eternal life. But to Him he leaves the greater testimony, that of works, as also He says, “I receive not testimony of men. The works which My Father has given Me, the same bear witness of Me.” Observe how much more effectual this was; for when he had thrown in a little spark, at once the blaze rose on high. For they who before had not even given heed to his words, afterwards say, “All things which John spoke were true.”
3. Besides, if he had gone about saying these things, what was being done would have seemed to be done from some human motive, and the preaching to be full of suspicion.
“And the two disciples heard him, and followed Jesus.”
Yet John had other disciples, but they not only did not “follow Jesus,” but were even jealously disposed towards him. “Rabbi,” says one, “He that was with you beyond Jordan, to whom you bore witness, behold, the same baptizes, and all men come unto him.” And again they appear bringing a charge against him; “Why do we fast, but your disciples fast not?” But those who were better than the rest had no such feeling, but heard, and at once followed; followed, not as despising their teacher, but as being most fully persuaded by him, and producing the strongest proof that they acted thus from a right judgment of his reasonings. For they did not do so by his advice, that might have appeared suspicious; but when he merely foretold what was to come to pass, that “He should baptize with the Holy Ghost, [and with fire,]” they followed. They did not then desert their teacher, but rather desired to learn what Christ brought with Him more than John. And observe zeal combined with modesty. They did not at once approach and question Jesus on necessary and most important matters, nor were they desirous to converse with Him publicly, while all were present, at once and in an off-hand manner, but privately; for they knew that the words of their teacher proceeded not from humility, but from truth.
Source: Homilies on the Gospel of John (New Advent)