What did Nicodemus probably understand Jesus to be saying?

Jesus was telling Nicodemus, in language Nicodemus was sure to grasp, that not only was He not speaking of any superficial or fleshly self-reformation, but He was in fact calling for something Nicodemus was powerless to do for himself. This punctured the heart of Nicodemus’s religious convictions. To a Pharisee like him, the worst imaginable news would be that there was nothing he could possibly do to help himself spiritually. Jesus had described Nicodemus’s case as utterly hopeless. Talk about harsh! But that is, after all, the very starting point of the gospel message. Sinners are “dead in trespasses and sins . . . by nature children of wrath . . . having no hope and without God” (Ephesians 2:1, 3, 12).