If polygyny is a sin, then Jesus owes both John the Baptist and the Pharisees apologies. Here's why:
Regarding the Pharisees…in Luke 16:18 Jesus cites the reason for His saying that the Pharisees were guilty of serving money more than God. He cites the case of divorce and remarriage, using John the Baptist (noted in the context) as a contrasting righteous prophet. This is an indication that He is referring to the
Herod/Herodias divorce/remarriage/incest case regarding which John was beheaded and the Pharisees were not. John lost his locusts and the Pharisees kept in their filthy lucre. They failed to hold Herod accountable for his wrongful divorce of his wife, the instigation of Herodias's divorce of Philip, and their incestuous remarriage to each other while John condemned him for the incest “and other sins.” So just one instance of such evils and Jesus goes after them for being culpably negligent.
And poor John the Baptist…beheaded…for standing up just once condemning the breach of Lev. 18:16 by Herod. Jesus was holding him up to the Pharisees as an example of a righteous prophet who did his duty in condemning Herod.
Now if polygyny is a sin...let's say on the basis of Lev. 18:18…the only real shot the anti-polygynists have against the practice…then why would God Himself (directly or through a prophet)…not have brought condemnation against ONE of the polygynists of the Old Testament for polygyny per se?
Take David for example. The man is called God’s friend. God gives him an everlasting covenant. But God is completely silent for the first 17 or so wives he took, and only condemns him for the woman he slept with…as not his wife, but the wife of another, Bathsheba. If you were a cop, would you let your friend drive drunk that many times (killing a female pedestrian each time) without a reprimand, and then collar him for driving in a stolen car and running over its owner? True, Solomon merits a reprimand, but then no one denies that he broke Deut. 17:17…a passage even the arch anti-poly writer, Richard Davidson, admits can’t be used to prohibit all royal polygyny much less the common variety.
Why condemn the Pharisees for missing one guy’s sin when God misses dozens? For that matter why jump on Pharaoh and Abimilech for the threat of their adultery with Sarai, when He is silent about Hagar? Why allow John to be beheaded because he felt obligated to stand up in one instance when God overlooks hundreds? And don’t give me the “God doesn’t need to condemn everything in particular if He condemns something in general,” because that misses the point: God NEVER confronts a polygynist for polygyny per se. Know of any other “sin” about which that could be said?
The fact is that in all law, including Biblical righteousness, condemnation bears the burden of proof. You have to have a law to claim it is broken. No law, no condemnation. People who say that polygyny is a sin purport to speak for God. If so, then let them show where God sets out that law.
If they say that polygyny was permitted by God’s righteous Law in the OT, but rescinds it in the NT, then let them show where God rescinds it in the NT (and don’t give me Jesus, Who says He did not come to annul any OT laws). And let them explain why God would see fit to change the practice of marriage 3/4 of the way down the historical pike. If they can’t make their case, then let them hold their tongues and their left foot of fellowship.
~ Dr. William Luck, posted on "Godly Patriarchy" 4-05-13
