Spiritual adultery is unfaithfulness to God. It is having an undue fondness for the things of the world. Spiritual adultery is analogous to the unfaithfulness of one’s spouse: “‘But like a woman faithless to her lover, even so have you been faithless to me, O house of Israel,’ says the LORD” (Jeremiah 3:20; see also Isaiah 1:21; 57:8; Ezekiel 16:30).The Bible tells us that people who choose to be friends with the world are an “adulterous people” having “enmity against God” (James 4:4–5). The “world” here is the system of evil under Satan’s control (John 12:31; Ephesians 2:2; 1 John 5:19). The world system, with its contrived and deceitful scheme of phony values, worthless pursuits, and unnatural affections, is designed to lure us away from a pure relationship with God. Spiritual adultery, then, is the forsaking of God’s love and the embracing of the world’s values and desires (Romans 8:7–8; 2 Timothy 4:10; 1 John 2:15–17).