If a believer marries again after a divorce, is that person living in a perpetual state of sin?
In Matt. 17:3-9 Jesus was arguing a point of law with some Pharisees. They believed a man could divorce his wife for any and all reasons based on a ruling Moses had handed down centuries earlier. Jesus repeated the Biblical doctrine that divorce for any other reason than adultery was against the law, and people who divorced and remarried for other reasons were committing adultery.
In the Law there is no provision for the forgiveness of future sins. The sacrificial system only covered past sins. A person could be absolutely righteous on one day, and lose it all the next (Ezekiel 33:18).
But under grace all the sins of a believer’s life were forgiven at the cross; past, present, and future (Colossians 2:13-14). If anyone is in Christ he or she is a new creation in God’s sight (2 Cor. 5:17), with a righteousness from God apart from the Law (Romans 3:21-24), made perfect forever by the Lord’s once-for-all-time sacrifice for sin (Hebrews 10:12-14). Our sins as a believer are not counted against us, but are attributed to the sin living in us (Romans 7:18-20). If this was not true, then Paul could not have promised that our inheritance (eternal life) was guaranteed when we believed (Ephesians 1:13-14).
Therefore, even though divorce for any reason other than adultery is still a sin, a born again believer who obtains a divorce and remarries is not living in a perpetual state of sin.