Biblical Answer

The question of what constitutes sexual immorality in Matthew 19 is a complex one. Jesus' statement in verse 10 is often interpreted as a prohibition against remarriage, but the context suggests that sexual immorality may include pre-marital unchastity, incest, or post-marital immorality. The term "sexual immorality" is related to the Old Testament concept of idolatry and unfaithfulness to God, and is often used in the New Testament to describe acts of sex outside of marriage. In this sense, sexual fidelity before marriage is presumed, and any act of sex outside of marriage is considered illicit.

The Bible is clear that sexual immorality is a sin that must be repented of, forsaken, and forgiven. In Matthew 19:9, Jesus states that anyone who divorces his wife, except for sexual immorality, and marries another woman commits adultery. This indicates that sexual immorality is a grounds for divorce, but it is not a justification for remarriage. In 1 Corinthians 6:9-10, Paul lists "men who practice homosexuality" as one of the sins that will keep someone out of the kingdom of God. Similarly, in Romans 1:26-27, Paul describes homosexual activity as a sin that is contrary to the natural order of creation. These passages make it clear that homosexual activity is considered a form of sexual immorality in the Bible.

In light of these passages, it is clear that Jesus' statement in Matthew 19:10 is a prohibition against remarriage due to sexual immorality. This includes pre-marital unchastity, incest, and post-marital immorality, as well as homosexual activity. The Bible teaches that sexual immorality is a sin that must be repented of, forsaken, and forgiven, and that it is a grounds for divorce, but not a justification for remarriage. Those who engage in sexual immorality are warned that they will face judgment and exclusion from the kingdom of God if they do not repent and turn to God. Ultimately, the Bible teaches that sexual immorality is a serious sin that can have eternal consequences, and that it is only through faith in Jesus Christ that we can be forgiven and restored to a right relationship with God.