Theophylact of Ohrid
Catena Aurea · Johannesevangelium 3
John answered and said, A man can receive nothing, except it be given him from heaven. Ye yourselves bear me witness, that I said, I am not the Christ, but that I am sent before him. He that hath the bride is the bridegroom; but the friend of the bridegroom, which standeth and heareth him, rejoiceth greatly because of the bridegroom’s voice: this my joy therefore is fulfilled. He must increase, but I must decrease.
Or thus; As, on the sun rising, the light of the other heavenly bodies seems to be extinguished, though in reality it is only obscured by the greater light: thus the forerunner is said to decrease; as if he were a star hidden by the sun. Christ increases in proportion as he gradually discloses Himself by miracles; not in the sense of increase, or advancement in virtue, (the opinion of Nestorius,) but only as regards the manifestation of His divinity.