By the time of the New Testament, sexual ethics are clarified (1 Corinthians 5–7; 1 Thessalonians 4:3–8). Incidents of incest in the Old Testament (e.g., Lot’s daughters in Genesis 19, Judah and Tamar in Genesis 38) are descriptive, not prescriptive—they show what happened, not what God approved. The New Testament frames such acts as sinful if they contradict God’s moral design.