Was Polygamy A Sin In The Old Testament?
Let's address the main objections to polygamy in the Old Testament.

Objection #1:
Although nothing in Scripture specifically prohibits polygamy, it is abundantly clear that the Bible condemns the practice of a man having multiple wives and concubines.

Rebuttal:
Statements similar to this have been made numerous times by the opponents of polygamy. Certainly, if God wanted to make it abundantly clear that He disapproves of polygamy, He could have done a much better job of doing so. When God disapproves of something, He isn't ambiguous about it. He has no problem telling people "Do this" and "Don't do that." It's interesting that even the opponents of polygamy confess that the Bible nowhere specifically prohibits it.But not only are there no clear statements in Scripture that God disapproves of polygamy, there were laws given by Moses to regulate it. Deuteronomy 21:15-17 is a specific instruction in the Law of Moses concerning any man with "two wives":

If a man has two wives, one loved and the other unloved, and they have borne him children, both the loved and the unloved, and if the firstborn son is of her who is unloved, then it shall be, on the day he bequeaths his possessions to his sons, that he must not bestow firstborn status on the son of the loved wife in preference to the son of the unloved, the true firstborn. But he shall acknowledge the son of the unloved wife as the firstborn by giving him a double portion of all that he has, for he is the beginning of his strength; the right of the firstborn is his (NKJV).

If polygamy really was a sin in Old Testament times, does it make sense that God would give rules to regulate the practice? That's like saying, "Well, I prefer that you don't commit adultery, but since you insist, here are a few tips to make your adulterous behaviour work." Absurd. Furthermore, adulterous behaviour was punished by stoning. There is no record of polygamists being stoned.

Objection #2:
Of course polygamy was a sin. Just look at all the marital problems polygamists had.

Rebuttal:
If polygamy is a sin simply because polygamists had marital problems, then it logically follows that monogamy is also a sin because certainly many monogamists have had and continue to have marital problems. The real question is, "Do polygamists have more problems than monogamists?"

The HBO TV series Big Love is about a polygamist played by Bill Paxton ("Twister," "A Simple Plan," "Titanic"), who has three wives, played by Jeanne Tripplehorn ("The Firm"), Chloë Sevigny (Oscar®-nominated for "Boys Don't Cry," "Dogville"), and Ginnifer Goodwin ("Walk the Line," "Win a Date with Tad Hamilton!"). Guess what? They have problems; if they didn't, it wouldn't be much of a show. But they usually manage to work things out. And at the end of the day, they all love each other. When asked, "Which wife do you love the most, Bill replies, "I love them all equally, but in different ways." Good answer.

But one might object: Yeah, but that's only a show. No polygamous marriage is like that. Just read the Bible. Men had favorites. Jealous wives were devastated. Polygamy can never work.

I have no doubt that many polygamous marriages are not as happy as the one portrayed on Big Love. And yes, the polygamous marriages recorded in the Bible were less than ideal. But the real questions are, "Has there ever been a happy polygamous marriage?" And "Is it possible for a polygamous marriage to work?" My guess is, the answer is yes.

Objection #3:
Polygamy Violates The "One Flesh" Principle. God intended, from the beginning, for one man to become one flesh within marriage to one woman, not two or more women. Genesis 2:24 states that when a man leaves his father and his mother, he shall cleave unto his wife: and they shall be "one flesh." The "one flesh" principle is also reiterated in Matthew 19:5,6, Mark 10:8, 1Corinthians 6:16, and Ephesians 5:31.

Rebuttal:
The Bible makes it clear that whenever a man has intercourse with a woman, the man becomes "one flesh" with EACH of those women, even if that woman happens to be a prostitute (See 1Corinthians 6:16). This, of course, does not imply that all acts of intercourse are necessarily wise or ethical. It simply means that all acts of intercourse between a man and a woman result in the two becoming "one flesh." In some cases, becoming one flesh is a good idea. In other cases, it is not. Therefore, if a married man has intercourse with a woman other than his wife, he becomes "one flesh" with that woman as well. This action does not necessarily negate him still being one flesh with his wife, as many claim, though some would argue that this could be legitimate grounds for divorce.

But what if the action is performed with the wife's knowledge and consent? Is it possible for all parties involved to make things work?

So the question is not: "Do sexual relations outside of marriage result in two people becoming one flesh." Obviously, they do. The real question is: "Is the sexual relationship beneficial to everyone concerned?"

Objection #4:
The Bible clearly states that Solomon disobeyed God by taking more than one wife. Therefore, polygamy is a sin.

Rebuttal:
Yes, the Bible does state clearly that Solomon disobeyed God by taking more than one wife. Solomon had 700 wives and 300 concubines. But that does not necessarily mean that polygamy per se is a sin. Here's why.

Although First Kings 11:6 does tell us that Solomon did do evil in the eyes of the Lord, it also states that Solomon did not follow the Lord completely, unlike his father David. Although there can be no doubt that David sinned grieviously when he committed adultery with Bathsheba, there is no indication that God disapproved of David having numerous wives and concubines. Unlike Solomon, all indications point to the fact that David did not allow his many wives and concubines to lead him away from God.

But not only did Solomon take many wives, those wives were ungodly idol worshippers. God warned Israel not to intermarry with Moabites, Ammonites, Edomites, Sidonians, or Hittites (Exodus 34:16). Scripture says these women would cause their husbands to worship pagan gods (1 Kings 11:2). And that's exactly what happened with Solomon. Solomon ignored God's warning and intermarried among those tribes. So the sin of Solomon seems to be marrying numerous ungodly women, not marrying numerous women per se. Perhaps if Solomon had married numerous godly women, they would've been a blessing.

Deuteronomy 17:17 cautions a king against taking many wives. It's curious, however, that God didn't simply say, "Just take one wife and no more, oh king." Perhaps, with all the responsibilities of being a king, most kings back then needed more than one wife. Furthermore, taken in context, kings are also warned against having many horses (verse 16) and many gold and silver coins (verse 17). Does this mean a king must only have one horse, one gold coin, and one silver coin? Of course not.

So how many wives are too many wives? According to Exodus 21:10, too many wives are more wives than a man can adequately provide for. Considering how rich Solomon was, it's a safe bet that he had no problem providing financially for his wives.

Objection #5:
Lamech was the first polygamist recorded in the Bible. Lamech was evil. Therefore polygamy is evil.

Rebuttal:
This is such a weak argument that it almost refutes itself. Here's the account, as recorded in Genesis 4:19-24:

Then Lamech took for himself two wives: the name of one was Adah, and the name of the second was Zillah.And Adah bore Jabal. He was the father of those who dwell in tents and have livestock. His brother's name was Jubal. He was the father of all those who play the harp and flute.And as for Zillah, she also bore Tubal-Cain, an instructor of every craftsman in bronze and iron. And the sister of Tubal-Cain was Naamah.Then Lamech said to his wives:

"Adah and Zillah, hear my voice; Wives of Lamech, listen to my speech! For I have killed a man for wounding me, even a young man for hurting me. If Cain shall be avenged sevenfold, then Lamech seventy-sevenfold" (NKJV).

Just because Lamech was the first polygamist recorded in the Bible, and just because Lamech was also a murderer, there is no valid reason to assume that there is or should be any association between polygamy and murder. That's like saying Hitler drank tea. Hitler was a sinful man. Therefore, drinking tea is a sin. Absurd!

Put another way, Genesis 4:19-24 also reveals other things associated with Lamech, which are also first recorded in this account. If we apply the same convoluted logic, we would have to conclude that the following are also sins, simply because they are the first recorded examples and because they are associated with Lamech and his family: dwelling in tents, having cattle, harps, organs, and artificers in brass and iron. Nobody would claim that these other examples are somehow sinful just because they are the first recorded examples in Scripture and just because they are associated with Lamech the murderer.

Objection #6:
Polygamists like Abraham, Jacob, and David were righteous men. However, they were not perfect. They were sinners, just like the rest of us. Therefore, just because they had numerous wives and concubines, that does not necessarily make polygamy ethical.

Rebuttal:
Although it is certainly true that Abraham, Jacob, and David were not perfect, it's almost unthinkable that all three of these men would have practiced polygamy if God had revealed to them it was a sin. Let's begin with Abraham as an example.

Was Abraham A Stupid, Unrepentant Polygamist?
Abraham was the father of the faithful. Abraham spoke face-to-face with God. He had to; the Bible had not yet been invented. Nevertheless, according to John MacArthur, Abraham and all other polygamists, were both stupid and disobedient.

Yet in order for Abraham to be disobedient, he would have needed advance knowledge that God disapproved of polygamy. Whether or not God ever told Abraham that polygamy was a sin is impossible to know. Nothing in the Bible records God giving Abraham such information. But for the sake of argument, let's pretend that God did tell Abraham polygamy was a sin. Does it make sense that Abraham, a model of obedience, would have disobeyed God in this matter? Unlikely.

First, let's establish that Abraham really was a model of obedience. According to Genesis 26:5, God said, "Abraham obeyed My voice and kept My charge, My commandments, My statutes, and My laws." This doesn't sound like an unrepentant, disobedient polygamist to me.

Of course, Abraham was not perfect or without sin. But God Himself said Abraham was obedient. This was a man who was willing to sacrifice his own son. This is also a man who, when God said "Jump," he asked, "How high?" In Genesis 12:1-4, the Lord told Abraham (then called Abram) to pack his bags, leave his country, and head towards parts unknown. Where? God said he'd tell him later. And what was Abraham's response? Verse 4 says he obeyed God and departed.

Does it make sense that the God who does not lie would have described Abraham as obedient if Abraham was clearly told by God that polygamy was a sin and Abraham went ahead and took multiple concubines anyway? Yet according to Genesis 25:6, Abraham had concubines shortly prior to his time of death. Nowhere does the Bible hint that God disapproved of Abraham's polygamous behavior.

Abraham is often criticized because he impregnated Hagar, who gave birth to Ishmael. But here are a few things to consider. According to Genesis 18:11, Abraham and Sarah were very old before either Ishmael or Isaac were born. Sarah was well past the normal age of childbearing. Yet God had promised Abraham a son. Sarah was the one who suggested to Abraham that he should sleep with Hagar. Abraham's purpose was to produce a child.

Of course, we all know how the story ends. Sarah eventually gives birth to Isaac, the child of promise. But Abraham didn't know this at the time.

The point is, if God had made it clear to Abraham that Sarah, not Hagar or someone else, was going to be the biological mother of the son of promise, Abraham probably wouldn't have heeded Sarah's prompting to impregnate Hagar. Furthermore, if it was not part of God's sovereign purpose for Hagar to become pregnant with Ishmael, he could have simply closed Hagar's womb.

If Abraham Was An Unrepentant Sexual Sinner, How Could God Have Given Him Eternal Life?
Since Genesis 25:6 says Abraham had concubines, plural, shortly prior to his time of death, if polygamy really is a sin, as many claim, then Abraham never repented of this sin. Few would argue that Abraham is not in Heaven. The story of Lazarus and the rich man makes it clear that he is (Luke 16:20-25). But how could Abraham be in Heaven if he never repented of his supposed sexual sin? The obvious answer is, Abraham did not go to his death bed as an unrepentant sexual sinner.

Numerous scriptures tell us that unrepentant sexual sinners will not inherit the Kingdom of God. First Corinthians 6:9-10 says:

Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived. Neither fornicators, nor idolaters, nor adulterers, nor
homosexuals, nor sodomites, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners will inherit the kingdom of God (NKJV).

Galatians 5:19-21 says virtually the same thing:

Now the works of the flesh are evident, which are: adultery, fornication, uncleanness, lewdness, idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambitions, dissensions, heresies, envy, murders, drunkenness, revelries, and the like; of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God (NKJV).

Revelation 21:8 also says the same thing:

But the cowardly, unbelieving, abominable, murderers, sexually immoral, sorcerers, idolaters, and all liars shall have their part in the lake which burns with fire and brimstone, which is the second death (NKJV).

Revelations 22:15 says:

But outside are dogs and sorcerers and sexually immoral and murderers and idolaters, and whoever loves and practices a lie (NKJV) .

If polygamy really were a sin, would Abraham now be in Heaven?.