When Nicodemus came to Jesus, Jesus told him what he had to do to enter into the Kingdom of God (go to heaven). Jesus didn't tell him he had to believe He was from God-- Nicodemus already believed that. He didn't tell him to go serve in the church-- Nicodemus was already doing that. He didn't tell him to become a church leader-- he already was. Jesus didn't tell him to go study the scriptures and read his "Bible"-- he already knew them and did study. Jesus didn't tell Nicodemus to do religious acts-- he was already doing religious acts.
Instead Jesus told him to be "born again". He told him he needed to "come back alive". Nicodemus was spiritually dead-- in trespasses and sin. He, like the rest of us, had sinned and come short of the glory of God. He was dead spiritually through Adam's sin in the garden. Sin and death came upon all mankind through Adam. (In the day that you eat of the tree you shall surely die.) Mankind spiritually died.
How do we come back to life spiritually? We must be born again. That was the message to Nicodemus and it is still the message to us today. The criteria hasn't changed. We still have to be "born again" if we are going to enter into heaven. Jesus doesn't say to us we have to do religious duties. He doesn't tell us that if we want to enter into heaven we have to join the church, shake the preacher's hand, get baptized, repeat a sinner's prayer, serve in the church, give offerings, etc. No, He tells us we have to be "born again". We have to come back alive spiritually. Only spiritually alive people enter into His Kingdom. Nothing, and no one, "dead" enters there.
The ONLY way to do this is through faith in Jesus' work at the cross. Jesus is the Way. Jesus takes away our sins. Jesus is Life. Jesus makes us brand new and a new person. Jesus turns our hearts that were dead in trespasses and sin into a brand new heart that is alive.
Have a great day. The criteria for eternal life is the same today-- you must be born again.
John 3:1-21; 14:6
Romans 3:23; 5:19