I get the impression that modern Christians put a lot of emphasis on Christ dying for our sins, bit reading the Bible, it is more about Christ being reborn... and that we die and are reborn in Christ... Is this right?
Reborn? You mean resurrected?
Rebirth--being born again--refers to a renewal and transformation of the human person from being estranged from God and out of communion with Him on account of our sinfulness to being a reconciled child of God's household. Like a prodigal returned home, a lost sheep returned to the pasture and comfort of the good shepherd.
The term Jesus uses in John chapter 3 in His discourse with Rabbi Nicodemus can be translated both as "born again" and "born from above"--it speaks of a re-birth from above (that is, from God). In this discourse Nicodemus responds to Jesus asking, "How can someone, already being born, be born again--do they re-enter their mother's womb?" Jesus expands what He says,
"Amen amen I say to you, unless one is born of water and the Spirit, they cannot enter God's kingdom. That which is born of flesh is flesh, and that which is born of the Spirit is spirit. Do not marvel that I said to you, 'You must be born again.' The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit."
Jesus connects "you must be born again" with "born of water and the Spirit"; that's a very clear reference to Baptism.
Why does Jesus mention Baptism to Nicodemus when Jesus has not yet instituted Christian Baptism yet? Jesus institutes Christian Baptism after His resurrection, as recorded in the Gospel of St. Matthew chapter 28, "Make disciples of all nations, baptizing them in the name of the Father, Son, and the Holy Spirit".
Jesus can, even before the institution of Holy Baptism, speak of the power of that baptism (for its power comes from Him, by His name and authority for the forgiveness of sins (see Acts of the Apostles 2:38) and by union with Christ--His crucifixion, death, burial, and rising again (Romans 6:3-4, Colossians 2:12, Galatians 3:27) because Baptism is prefigured in the Jewish practice of ritual washing (tevilah) which is often translated and called "baptism" in Greek.
In Judaism, both two thousand years ago and today, when a Gentile was undergoing the process of conversion to become a Jew there were a number of steps in that conversion process. Obviously for males (adults and children) conversion to Judaism meant circumcision; but for everyone (regardless of age or sex) a washing in the tevilah by immersion into water (usually at a mikveh, a bath specifically intended for tevilah) was essential. This conversion-tevilah wasn't just a meaningless bath, rather it signified the transformation and rebirth from being outside of the covenant people of God (a Gentile) to now being one of God's covenant people (a Jew).
So after Jesus says what He says to Nicodemus above, He continues,
"Are you a teacher of Israel and yet you do not know these things?"
Jesus' question presumes Nicodemus to know these things, or that he should get it--but for some reason doesn't. Nicodemus, a rabbi, should have picked up on what Jesus was saying. Christian tradition, does, of course say that Nicodemus did eventually get it, as Nicodemus would be baptized and become a Christian after Jesus' passion and resurrection. But here, in this text, Nicodemus seems either confused or, possibly, hostile in his questioning; but Jesus nevertheless answers and addresses Nicodemus seriously.
Baptism, in traditional Christian teaching, is the ordinary means of God to bring about our regeneration--our new birth by the power of the Holy Spirit; by giving us faith, a new and clean heart and conscience before God, and all the promises and gifts associated with Baptism in Scripture.
And that's important: Regeneration is the work of God to take us as we were and are in our weakness, our sinfulness, and faithlessness and give us faith, through which the full work of Christ is appropriated to us (Justification) and our being worked upon by God through the ongoing power and work of the Spirit in our lives as we live as Christ's disciples and live in the grace and truth of God's gifts and promises as members of God's Household: His Church.
Jesus wasn't "reborn", He didn't need to be regenerated because He's Jesus--He's the One who gives us new birth, because we need it. Our regeneration--our new birth from God--sets us in and with Christ and our being changed and renewed day-by-day into the image and likeness of Jesus our Lord.
-CryptoLutheran