Nicodemus claims to know that Jesus is from heaven, because in his opinion the miracles are kind of irrefutable proof of it. Jesus, however, rejects this statement of Nicodemus, because Nicodemus (victory of the people) is in no position to judge this. He is not descended from above (falsely translated as born again) and therefore he has no knowledge of the things from above, which is heaven. He is a person from earth (from below), a man born in the flesh without the holy spirit. He has only knowledge about earthly things.