John 6:40

Verse 40. Everyone which seeth the Son, and believeth on him. It was not sufficient to see him and hear him, but it was necessary, also, to believe on him. Many of the Jews had seen him, but few believed on him. Jesus had said in the previous verse that all that the Father had given him should be saved. But he never left a doctrine so that men must misunderstand it. Lest it should be supposed that if a man was given to him this was all that was needful, and lest anyone should say, "If I am to be saved I shall be, and my efforts will be useless," he states here that it is necessary that a man should believe on him.