Q. What is regeneration? Being born again? Are these synonymous with each other? I always believed that at Pentecost is when man first became born again. OT saints were saved through faith and obedience to the law, and when they died, they went to Abraham’s bosom until Jesus took them to paradise because their sins hadn’t been atoned for yet and they weren’t born again.
A. Being born again is when you confess that you’re a sinner and ask the Lord to forgive you and come into your heart. The authority to ask this was made possible by the Lord’s death and resurrection. (John 1:12) Although the word Greek word translated regeneration (KJV) or rebirth (NIV) in Titus 3:5 is different from the one translated born again in John 3:3 they both come from the same root which means to become or come into existence. Therefore regeneration is another way of saying born again.
You’re correct in saying that Old Testament saints waited in Abraham’s Bosom until the Lord’s death because it took the shedding of His blood to give humanity access to Heaven. But Abraham’s Bosom and Paradise are two names for the same place. The first is a Hebrew idea and the 2nd is Greek. Jesus took the Old Testament saints to Heaven.