Most assuredly, I say to you, We speak what We know and testify what We have seen, and you do not receive Our witness.
John 3:11
Surrounding context
3:10 Jesus answered and said to him, "Are you the teacher of Israel, and do not know these things?
3:11 Most assuredly, I say to you, We speak what We know and testify what We have seen, and you do not receive Our witness.
3:12 If I have told you earthly things and you do not believe, how will you believe if I tell you heavenly things?