Jesus told you in John 3:3-5
Except a man be born again, he cannot see the kingdom of God.
Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God. (KJV)
A poor translation - better is born from above or born anew
Born of water and of the Spirit - baptism in water; what Paul calls in Tin 3:5 "the bath of rebirth and renewal by the holy Spirit," (NAB).
Paul gives us the same theme of death and new life (born again/ born anew) in Col 2:12-13
You were buried with him in baptism, in which you were also raised with him through faith in the power of God, who raised him from the dead. 13 And even when you were dead [in] transgressions and the uncircumcision of your flesh, he brought you to life along with him, having forgiven us all our transgressions
And in Rom 6:4
We were indeed buried with him through baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, we too might live in newness of life.
That is why Jesus told the apostles in Mt 28:19 "Go, therefore, and make disciples of all nations, baptizing them in the name of the Father, and of the Son, and of the holy Spirit," and said in Mk 16:16 "Whoever believes and is baptized will be saved"