When someone becomes a Christian, he becomes a brand new person inside. The old passes away, a new life has begun. 2 Corinthians 5:17 (LB)
God created humans to have fellowship with Him. but they defied God by sinfully going their own way. As a result, we need Gods saving grace to end our alienation from Him. Salvation comes only through Gods grace - not human effort - and must be received personally by repentance and faith. At the end, everyone will experience bodily resurrection and the judgement. Only Believers will enjoy eternal fellowship with God.