Neither shall (a king) multiply wives for himself, lest his heart turn away (Deuteronomy 17:17)

The Hebrew word translated ‘multiply’ isרָבָה rabah and it is found in the first commandment given to humankind.

‘Be fruitful and multiply…’ (Genesis 1:28)

But in the head quotation, Moses is relaying instructions for the establishment of monarchy for the time when the Israelites will demand that they have a king as do other nations.

Of course, this regulation was ignored; not least by Solomon who had greatly multiplied the number of his wives, and was duly led astray.

… he had seven hundred wives, princesses, and three hundred concubines; and his wives turned away his heart. (1 Kings 11:3)

In fact, the Law of Moses did not proscribe polygamy but sought to regulate it, and not just with kings.  As here regarding the care of the first wife:

If (a man) takes another wife, he shall not diminish her food, her clothing, and her marriage rights.  (Exodus 21:10)

Polygamy was tolerated by God and occurred almost immediately the gates of Eden were shut with Lamech, from the line of Cain, taking two wives (Genesis 4:19).  

God had decreed the perfect relationship in Eden: God, Man and Woman.  Adam was necessarily monogamous, as there were no other women.  But only after his expulsion, when Adam renamed ‘the Woman’, Eve – as she became ‘the mother of all living’ – did humankind multiply.  Perhaps, for there to a rapid increase, God overlooked the Edenic model of monogamy, so that humanity may be fruitful, as commanded.  And, it should also be noted, in those days, the father and husband offered protection, so if women were ‘surplus’ in the household, then better they marry even if the man had wives aplenty.

The institution of the ‘Levirate Marriage’ sanctioned polygamy and was decreed for this very purpose of security.  Here a brother-in-law was required to marry his brother’s widow, even if he was already married (Deuteronomy 25:5).

When Jesus taught on divorce and adultery, he implicitly restated God’s model of monogamy, because his teaching only makes sense in that context, not in one of multiple wives.  And, in restating the passage from Genesis, God’s word passes from commentary to commandment:

“Have you not read that He who made them at the beginning ‘made them male and female,’ and said, ‘For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh’? So then, they are no longer two but one flesh. Therefore, what God has joined together, let not man separate.”  (Matthew 19:4-6)

But in this is found a mystery that only the apostles would have revealed to them, as they fulfilled their commission to establish Christ’s Church:

For we are members of His body, of His flesh and of His bones. “For this reason, a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh.”  This is a great mystery, but I speak concerning Christ and the church.  (Ephesians 5:30-32)

It is the Church that is foreshadowed in Eden.  In God, Man and Woman is found the sacred communion of God, Christ and Church.

The Church is Christ’s bride, as John the Baptist intimated, doubtless not fully realising it to be a prophetic statement:

‘I am not the Christ,’ but, ‘I have been sent before Him.’ He who has the bride is the bridegroom…’

John was the last of the Old Testament prophets, in whose forthtelling marriage and adultery had always been the metaphor for Israel’s unfaithfulness, as here the LORD speaks to Jeremiah:

‘Then I saw that for all the causes for which backsliding Israel had committed adultery, I had put her away and given her a certificate of divorce; yet her treacherous sister Judah did not fear, but went and played the harlot also. So it came to pass, through her casual harlotry, that she defiled the land and committed adultery with stones and trees.’  (Jeremiah 3:8-9)

In regard of the sacred ‘marriage’ of Israel and God, there was no toleration of adultery, nor license for polygamy.  God was jealous of Israel, who said, ‘hear, O Israel, the Lord our God, the Lord is one!’ Deuteronomy 6:4) there was to be no pantheon of gods or syncretism and idolatry was anathema.

His commandments are founded on this monotheistic declaration – commandments that if observed would multiply Israel (Ibid 6:3).

While God abhorred idolatry, polygamy within intermarital relations he tolerated and regulated through the Law – until Jesus, when monogamy is then commanded.  Then marriage between one man and one woman can now be understood as the foretaste of a sacred union, the mystery to which Paul alluded.   All humanity that have submitted to Christ are joined with each other and wedded to Christ.

For as the body is one and has many members, but all the members of that one body, being many, are one body, so also is Christ. For by one Spirit, we were all baptized into one body – whether Jews or Greeks, whether slaves or free – and have all been made to drink into one Spirit.  (1 Corinthians 12:12-13)

If this is not easily understood, all will become clear at the wedding feast, which Jesus Christ has prepared for all, as the apostle, John, sees in a vision:

And I heard, as it were, the voice of a great multitude, as the sound of many waters and as the sound of mighty thunderings, saying:

“Alleluia! For the Lord God Omnipotent reigns! Let us be glad and rejoice and give Him glory, for the marriage of the Lamb has come, and His wife has made herself ready.” 

And to her it was granted to be arrayed in fine linen, clean and bright, for the fine linen is the righteous acts of the saints.  Then he said to me,

“Write: ‘Blessed are those who are called to the marriage supper of the Lamb!’”  (Revelation 19:6-9)

This is God’s purpose for redemption outworked as presaged by the institution of monogamous marriage.