In reply to Theresa Salka.

This verse is connected to what Jesus had been telling Nicodemus, although the connection is not immediately obvious. The verse is cited in the Ante-Nicene commentaries of Tertullian, Hippolytus, Novatian, Archelaus, and is also included in the ancient Syriac Diatessaron of Tatian.

Nicodemus understood Christ to be a great teacher and perhaps a prophet because of the miracles he had performed (John 3:2). In verse 13, Jesus is extending his dialog with Nicodemus to reveal that He is much more than a prophet. No mere man, he says, hath ever ascended up to heaven as he will.