Recently, I received on my blog a comment from an anonymous source asking, "When did the New Testament start and were the disciples born again" Great questions. I confess I don't have all the answers but I have given this some thought.
If the word Testament is another word for Covenant, than I believe the New Testament (Covenant) started after Jesus' ascension. After His resurrection, Jesus had to take His blood to the Mercy Seat in Heaven to make atonement for Adam's sin. Remember how when Mary first thought that He was the gardener, but when she recognized Him she wanted to embrace Him? His response was, "Don't touch Me, I have not yet ascended!" Could that of meant that the Mercy Seat was waiting for His blood? I don't know. God has His timing in everything.
I have also given some thought to the last supper, when Jesus lifted the cup of redemption saying, "this is my blood shed for you. this bread is my body broken for you." Could this be the beginning of the New Testament? Both Jeremiah and Ezekiel prophesied that a New Covenant was going to be made.
Some people think that the New Testament started with St. Paul, and that Jesus was only speaking to the Jews. Personally, I think it had to do with the heavenly Mercy Seat. It required a holy, righteous, prefect sacrifice of a man. Jesus, God's Son, was the 'only one' who could fulfilled it's requirements. After His death and resurrection, the curtain was torn in the temple and the, the believer could now enter the Throne of Grace by the blood of the Lamb, Jesus.
To attempt to answer 'Were the disciples born again" with biblical proof?" I don't think there is an explicit place where it says, "The disciples were born again". I believe it has been implied. One possibility might be in John 20:22. After His resurrection, Jesus appeared to the disciples in the upper room. He breathed on them saying,"Receive the Holy Spirit". The disciples now had the Holy Spirit in them, Later at Pentecost, the disciples received the 'power' to witness the resurrection. Their lives were changed. Peter especially became bold with His speech.
Today, as disciples of Jesus,we are born again. The Lord has breathed into our spirits eternal life. But the question remains, have we received the "power" the witness the resurrection of our Lord? Are we ready to testify His gospel, face persecution, be hated by the world, love our enemies, forgive those who offend us, do we love one another?" Without His power released in us, we can't forsake the world and only be true to Him.