John 3:11-13 (King James Version)
11 Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness. 12 If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you of heavenly things? 13 And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven.