During the Feast of Passover, Jesus cleared the temple by driving out animals meant for sacrifice. Although the authorities do not question Jesus' actions, they want evidence of his authority. They ask for a sign to prove it, most likely seeking proof of his prophetic credentials. John explains that the Jews had misunderstood Jesus' words and thought they referred to the physical temple, but Jesus was referring to his own body.

There were additional signs, not described in detail, which led many others to also believe (v. 23). In verses 23 and 24, John uses a word play on the verb "believe." Many people believed in Jesus, but Jesus did not believe in them. John explains that Jesus knew what was in their hearts. Since Jesus knew everyone's hearts, he knew that they needed to be born again, and he knew who would accept or reject him. Even though some people were temporarily attracted to Jesus because of his miracles, he did not trust them because he knew their true intentions.

In 3:1-15, the conversation between Jesus and Nicodemus explains the details of this new birth introduced in John 1:12-13. John portrays Nicodemus as a respectful character who doesn't make assumptions about Jesus but talks to him directly. Although Nicodemus cannot comprehend Jesus' words in this passage, he is presented as a sympathetic character by John, not hostile or confrontational. This passage contains a lot of drama. Nicodemus, a Pharisee and a leader of the Jewish people comes to see Jesus because he believes that God is working through him (verse 2). Nicodemus was probably aware of the many beliefs and expectations surrounding Jesus, as outlined in verses 1:19-51. He brings his hopes, expectations, and conclusions to Jesus, and their conversation offers lessons for all generations. Through their exchange, Jesus makes bold claims about how he fulfills promises from the Old Testament.

The word "again" used here can also mean "from above," which is a double meaning. The idea of being born "from above" refers to 1:12-13. Nicodemus is an example of the people who are attracted to Jesus because of his miracles but are not trusted by him. Even though Nicodemus has seen Jesus' miraculous signs, he cannot see God's kingdom unless he is born again. By referring to himself as the Son of Man, Jesus provides Nicodemus with another Old Testament reference that helps him understand Jesus' identity. Jesus implies that he is the Son of God by alluding to Proverbs 30:4 and then identifies himself as the Son of Man described in Daniel 7:13-14. Nicodemus should believe in Jesus because of who he is.

Jesus has come down from heaven and can therefore speak about heavenly things. Nicodemus should also trust that if he speaks truthfully about earthly things, he can explain heavenly things. Jesus references the account of Numbers 21, where the people face death due to the serpents that the Lord had sent among them as punishment for their sins. Disbelief in Jesus will lead to punishment. God told Moses to create a bronze snake and lift it as a symbol of the judgment that had been placed on the people.

Similarly, Jesus, who brings judgment, would later be lifted up on the cross. The people who looked at the bronze serpent were saved from the serpent's venom. Similarly, those who look to Jesus when he is lifted up will be saved from his judgment and given eternal life.