"Menage a Trois"
We have determined that there is no Scriptural condemnation of female-female sexual relations, except perhaps if we expanded the definition of whoring (zanah) to apply regardless of gender. In any event, there are no specific prohibitions as there are for male-male relations. So the question remains as to where the boundaries lie in the female-female relationship within a polygynous marriage.
To be completely honest, I'm not sure I have a Scriptural answer for this one. Elohim's Word does not prohibit a polygynous man from enjoying sex with his wives simultaneously. It is neither condemned nor approved in the Bible, and although I have an opinion on this matter, I believe it's important to stick close to what the Bible says (or doesn't say) in this regard.
Certainly the best way to look at this issue is to clarify what "sin" is. People can debate all day long about whether such-and-such practices are advisable, beneficial, hurtful or dangerous. But when it comes to defining something as "sinful", our opinions cease to matter.
Everyone doing sin also does lawlessness, and sin is lawlessness. (1 John 3:4, The Scriptures)
Sin is specifically defined in 1 John 3:4 as "lawlessness", or "transgression of the law". That gives us a clear objective point on which to discuss whether something is sin or not. The Bible lists the various things which in Elohim's eyes are sexually immoral: whoring (zanah), a man uncovering the nakedness of specific family members, a man uncovering the nakedness of a woman during her menses, adultery, a man having anal sexual intercourse with another male, and a man or a woman having sexual intercourse with an animal. Beyond that, the Bible is pretty much quiet.
We are told nothing about sexual conduct within a polygynous marriage. In fact, the only piece of love-making we have in the Scriptures, the Song of Solomon, describes the intimacy of one man and one woman and has traditionally been used as a lover's manual over the centuries. It is my belief that everything one needs to know regarding sexual conduct in a marriage is to be found in that book.
I personally would be unwilling to add restrictions that Elohim did not. We do not require special permission to do something that Elohim did not specifically prohibit while prohibiting a series of other relationships in the same area. He went to extraordinary lengths to cover the various prohibited sexual practices and yet there is no mention anywhere in Scripture regarding female-female intimacy.
It is quite likely that the very reason that Scripture is silent on this issue is due to polygynous marriages. It may simply be that Elohim chose not to place unmanageable restrictions within the marriage bed, such as "You stay on this side", "You face this way", "No moving your arm past this point", etc. I doubt that this was a total non-issue in a population of millions where polygynous marriage was common.
Where the Scriptures do not speak, we must seek personal direction from the Spirit of Elohim. Where we are unsure, we must live by our conscience to some degree while we discover the truth. But I must urge caution to those living within a polygynous marriage relationship today:
However, not all have this knowledge. But some, being aware of the idol, until now eat it as having been offered to an idol, so their conscience, being weak, is defiled. But food does not commend us to Elohim, for we are none the better if we eat, nor any worse for not eating. But look to it, lest somehow this right of yours becomes a stumbling-block to those who are weak. For if anyone sees you who have knowledge eating in an idol's place, shall not his conscience, if he is weak, be built up to eat food offered to idols? So this weak brother, for whom Messiah died, shall perish through your knowledge! Now sinning in this way against the brothers, and wounding their weak conscience, you sin against Messiah. Therefore, if food makes my brother stumble, I am never again going to eat meat, lest I make my brother stumble. (1 Corinthians 8:7-13, The Scriptures)
As followers of Yahushua, we must take special care not to become a stumbling block to our brothers and sisters in Messiah. This is an exceedingly sensitive subject and one that could easily be misunderstood. It should be obvious that a woman doesn't need to be "abnormal" at all for enjoying her beloved sister-wife making love to their common husband. At the same time, we should be reluctant to place specific restrictions that Elohim did not, even for practices which we don't particularly want to engage ourselves. The best advice I could give on this matter is to take the "if it's not prohibited, it is permitted" stance, while at the same time clarifying that if you're in doubt, avoid it altogether.
Conclusion
Messianic believers within Western society have an inbuilt doctrine inherited from the Catholics and Protestants which teaches that sex is somehow "nasty" and "dirty", even between married people. That has largely been overcome, for good and evil, as a result of the 1960's youth rebellion, except now things have swung in the opposite direction where sex has been exalted and blown out of proportion relative to its true place within the human experience. If Biblical Polygyny is going to be successful and find a proper balance, it must excise both of these destructive elements.
This is a very difficult matter for some believers to accept. I myself struggled with this revelation for over a year, studying Scriptures for hours at a time, trying to find evidence to the contrary. But in the end, I had to accept what was written in His Word. There are no Scriptures anywhere in the Bible that indicate polygyny is wrong or sinful, and I can no longer condemn such marriages. In most cases, one-wife marriages will probably continue to be the most common arrangement. No man should be condemned for only having one wife, but neither should we condemn those with multiple wives.
My personal challenge to you is to search through your Bibles at home, research the Scripture references given in the Hebrew and Greek, and find anything that substantiates a condemnation of polygyny. Go through the Torah of Moses. Search the book of Proverbs. Read through the Prophets. Examine the Messianic Scriptures carefully. Check and recheck several times just to be sure. There is no verse of Scripture anywhere in the Bible that ever condemns polygyny as sin, or a work of the flesh, or represents it as being discontinued on account of the New Covenant.
Understanding polygyny and accepting it as a valid and Biblical form of marriage today is very crucial, because it brings healing and knowledge to those who have found themselves divorced by a spouse, as well as giving understanding and wisdom to missionaries who preach the gospel to polygynous families in other countries. How many marriages in other lands have been destroyed because we in the West with our Western culture and arrogant feeling of superiority have gone and demanded that others must divorce all but one wife to be saved?
Please understand my heart in this matter. At the time I am writing this article, I am a 38-year-old man, happily married to a wonderful 27-year-old Godly woman for the past 7 years. She has taught me, by her own example, more about living a Messiah-centered life than I learned in my first 30 years. When I first discovered this information regarding polygyny in Scripture, I was very much against it and needed to ask Yahweh to touch my heart and get my thinking lined up with His. Over time, I began to discern the spiritual implications of polygyny related to the body of Messiah, and of marriage in general. Today I find myself reading Scriptures with a newfound clarity, as though a veil of fog had been lifted from my eyes. If nothing else, I praise Yahweh for giving me the wisdom to understand His Word better.
Although my wife and I have discussed the polygyny matter amongst ourselves and she wouldn't object to such a union, I nevertheless believe it would take an exceptional man and exceptional women to make a polygynous marriage work properly in today's world. It certainly is not for most people with a Western-culture upbringing. Even if I can't see myself in that role, that doesn't mean I can condemn other believers who want to pursue a polygynous marriage for themselves.
No matter how much you may have difficulty in accepting this principle, I urge you to submit to the Word of Elohim alone as the final authority, NOT the teachings of man.