What does the Bible say about the sin of sexual immorality?

The Bible teaches that sexual immorality is a serious sin, as highlighted in Hebrews 13:4, which states that marriage is honorable in all and that the bed is undefiled. In Genesis 34, we see the tragic consequences of sexual sin through Dinah's defilement by Shechem. Such actions illustrate the dangers of fornicating outside of God's design for marriage. God warns us against sexual immorality because it corrupts the sanctity of marriage and can lead to devastating emotional and relational consequences.