The Right of the Firstborn
Deuteronomy 21: 15 If a man has two wives, and he loves one but not the other, and both bear him sons but the firstborn is the son of the wife he does not love, 16 when he wills his property to his sons, he must not give the rights of the firstborn to the son of the wife he loves in preference to his actual firstborn, the son of the wife he does not love. 17 He must acknowledge the son of his unloved wife as the firstborn by giving him a double share of all he has. That son is the first sign of his father’s strength. The right of the firstborn belongs to him.
Nowhere in the bible is polygamy condemned. In the Old Testament, polygamy is never directly declared to be legal, but there are laws where it is assumed to be fine. The law above is one example. The law permits polygamy since it regulates how a man is to provide inheritance to children of multiple wives.
Almost every biblical patriarch had multiple wives. Jacob had 2 wives. David had 8 wives. Solomon had 700 wives and 300 concubines. There are many other examples.
I have heard many Christians claim in recent years that the bible has promoted a marriage as 1 man and 1 woman. The bible does not support these Christians’ claims.
I have heard many Christians claim that not following the bible will result in moral relativism. However, these Christians are being hypocritical regarding polygamy. Is polygamy wrong? Most Christians say yes. They do not get this moral value from the bible. The change in moral status of polygamy is a result of cultural changes over time. If we follow the bible, polygamy is fine. The fact that modern Christians claim polygamy is wrong is an example of moral relativism.