Affinity

Affinity in the biblical context refers to relationship created through marriage or political alliance rather than blood. The term is used in 2 Chronicles 18:1 to describe the marriage alliance between Jehoshaphat of Judah and the house of Ahab of Israel — Jehoshaphat made affinity with Ahab by the marriage of his son Jehoram to Athaliah, Ahab's daughter. Similarly, Solomon's affinity with Pharaoh through marriage (1 Kings 3:1) is noted as part of his foreign policy, though subsequently criticized in the account of his foreign wives who led him into idolatry.

The Mosaic law regulated affinity through an extensive list of prohibited degrees of relationship (Leviticus 18:6–18), specifying the classes of relatives by marriage with whom sexual relations were forbidden. These regulations shaped the boundaries of permitted marriage within Israelite society and were treated in Second Temple Judaism and later halakhic tradition as binding definitions of incest even beyond the letter of the text.