We prepare for the Kingdom by living according to the rules of the Kingdom now. Jesus explained to Nicodemus how one can enter the Kingdom of God. He told him that one must "be born again" (John 3: 1-8). This process begins with baptism, which means the death of the old sinful man and the beginning of a new life dedicated to Christ (Romans 6: 1-5). This culminates in a change of mortal flesh and blood to an immortal spirit at the return of Christ (1 Corinthians 15: 50-53; 1 Thessalonians 4: 16-17).