Nothing could be further from the truth.
The Old Testament, in fact, contains a sustained polemic against polygamy and in favor of monogamy.
That line of reasoning, however, is often implicit rather than explicit, because the Hebrew Scriptures use narrative didactic instead of propositional didactic.
Even an erudite reference work like the Dictionary of Biblical Imagery make the simple mistake of assuming that the text allows for Solomon’s or Jacob’s marriages:
Both the Old and New Testaments agree that adultery is sin. In the OT any married woman who has intercourse with a man other than her husband is guilty of adultery, as is any man who has sex with another man’s wife. But it is sometimes acceptable for a man to have multiple wives or concubines. Jesus holds up a more consistent standard in the NT, with both men and women called to be faithful to their one spouse.
The Hebraic style of the Old Testament prefers narrative didactic: showing concrete examples. The OT is less inclined to use propositional didactic: stating general principles. So we do not find a clear statement in the text that polygamy is wrong.
Nevertheless, the text contains expansive argumentation against polygamy. Consider the description given of Lamech, the first recorded polygamist in human history. He is clearly painted as someone whose example should not be followed.
The polygamy of Jacob results in negative consequences: jealousy and envy between Rachel and Leah. The text is preaching against polygamy.
Solomon’s multiple wives are explicitly linked to his spiritual downfall.
Abraham was not strictly guilty of polygamy, because he was not married to more than one woman at the same time. The text, however, still questions his behavior, inasmuch as he had children with his two successive wives, Sarah and Keturah, with his domestic servant Hagar, and with an unspecified number of concubines. The result was a lack of domestic tranquility as the children of at least five different mothers competed with each other. The text is highlighting the suboptimal consequences of Abraham’s indiscriminate procreation.
Simultaneously, the text points to the virtues of monogamy. In the various prophetic passages which employ the metaphor of God as husband and the nation of Israel as His bride, the paradigm is distinctly monogamous.
The reader should understand that the Old Testament offers a narrative, or a string of related narratives, which together constitute a condemnation of polygamy and an endorsement of monogamy. According to the text, polygamy is never OK.
