John 1:30

This is he, of whom it is said
Either the day before, as in ( John 1:27 ) , or some time before that, ( John 1:15 ) , when he first began to baptize, even before Christ came to be baptized by him, and before he personally knew him; see ( Matthew 3:11 Matthew 3:13 ) .

After me cometh a man;
not a mere man, but the man God's fellow: and this is said, not because he was now a grown man, or to show the truth of his human nature; but seems to be a common Hebraism, and is all one as if it had been said, "after me cometh one", or a certain person: for the sense of this phrase, and what follows, (See Gill on John 1:15).