John understood Isaiah's words of Christ's ministry. Some would believe, while others, although seeing many signs, would not believe. For it was God who blinded their eyes andhardened their hearts. The fact is (as John goes on to articulate) that the Jews loved the glory of man rather than God. Obviously Christ was not a glorious man 
according to societal standards. He was weak, with no place
to lay his head, no legalistic credentials, just a carpenter's son from Nazareth... yet he was the Son of God!
John 12:43 "For they loved the glory that comes from man more than the glory that comes from God." Is. 2:22 "Stop regarding man in whose nostrils is breath for life, of what account is he?", Jer. 9:23,24 "Let not the wise man glory in his wisdom, let not the mighty man glory in his might, let not the rich 
man glory in his riches, but let him who glories, glory in this that he knows and understands me, that I am the LORD who practices steadfast love, justice, and righteouness in the earth. For in these things I delight."
man glory in his riches, but let him who glories, glory in this that he knows and understands me, that I am the LORD who practices steadfast love, justice, and righteouness in the earth. For in these things I delight." Man is never a repository of worth unto himself.
He is a conduit epuipped with features and faculties
to praise and glorify God.
