It wasn’t until sin made man fall (Gen. 4:23) that polygamy occurs. Cain was cursed, Lamech is a descendent of Cain and the first to practice polygamy. The first time polygamous relationship is found in the Bible is with a thriving rebellious society in sin; when a murderer named “Lamech [a descendant of Cain] took for himself two wives” (Gen.4:19, 23).