Nicodemus was a member of the Jewish legislative and judicial assembly known as the Sanhedrin. He came to JESUS at night to ask him a few burning questions. The conversation they had tells you everything you need to know about the most important issue you'll ever have to decide: your eternal salvation. In other words,  whether or not you'll go to Heaven after you die. Here is the discourse as recorded in the first 21 verses of the third Chapter of The Gospel According To John as presented in the Berean Study Bible:

 

1 Now there was a man of the Pharisees named Nicodemus, a leader of the Jews.

2 He came to Jesus at night and said, “Rabbi, we know that You are a teacher who has come from God. For no one could perform the signs You are doing if God were not with him.”

3 Jesus replied, “Truly, truly, I tell you, no one can see the kingdom of God unless he is born again.”

4 “How can a man be born when he is old?” Nicodemus asked. “Can he enter his mother’s womb a second time to be born?”

5 Jesus answered, “Truly, truly, I tell you, no one can enter the kingdom of God unless he is born of water and the Spirit.

6 Flesh is born of flesh, but spirit is born of the Spirit.

7 Do not be amazed that I said, ‘You must be born again.’

8 The wind blows where it wishes. You hear its sound, but you do not know where it comes from or where it is going. So it is with everyone born of the Spirit.”

9 “How can this be?” Nicodemus asked.

10 “You are Israel’s teacher,” said Jesus, “and you do not understand these things?

11 Truly, truly, I tell you, we speak of what we know, and we testify to what we have seen, and yet you do not accept our testimony.

12 If I have told you about earthly things and you do not believe, how will you believe if I tell you about heavenly things?

13 No one has ascended into heaven except the One who descended from heaven—the Son of Man.

14 Just as Moses lifted up the snake in the wilderness, so the Son of Man must be lifted up,

15 that everyone who believes in Him may have eternal life.

16 For God so loved the world that He gave His one and only Son, that everyone who believes in Him shall not perish but have eternal life.

17 For God did not send His Son into the world to condemn the world, but to save the world through Him.

18 Whoever believes in Him is not condemned, but whoever does not believe has already been condemned, because he has not believed in the name of God’s one and only Son.

19 And this is the verdict: The Light has come into the world, but men loved the darkness rather than the Light because their deeds were evil.

20 Everyone who does evil hates the Light, and does not come into the Light for fear that his deeds will be exposed.

21 But whoever practices the truth comes into the Light, so that it may be seen clearly that what he has done has been accomplished in God.”

Henry Ossawa Tanner (1859–1937 Black-and-white print reproduction of painting "Nicodemus." From the materials for the Alaska-Yukon-Pacific Exposition of 1909, held in Seattle. Catalogue of Fine Arts Gallery and Exhibit of Arts and Crafts, California Building - Page 41.