john 1:31 And I knew him not: but that he should be made manifest to Israel, therefore am I come baptizing with water. - Free Bible Online

      31-34. knew him not--Living mostly apart, the one at Nazareth, the other in the Judean desert--to prevent all appearance of collusion, John only knew that at a definite time after his own call, his Master would show Himself. As He drew near for baptism one day, the last of all the crowd, the spirit of the Baptist heaving under a divine presentiment that the moment had at length arrived, and an air of unwonted serenity and dignity, not without traits, probably, of the family features, appearing in this Stranger, the Spirit said to him as to Samuel of his youthful type, "Arise, anoint Him, for this is He!" (1Sa 16:12). But the sign which he was told to expect was the visible descent of the Spirit upon Him as He emerged out of the baptismal water. Then, catching up the voice from heaven, "he saw and bare record that this is the Son of God."

JFB.