1. In the book of Genesis – the beginning of the creation and ordination of all things, God essentially instituted Holy matrimony – the spiritual union of a man and a woman called ADAM and EVE respectively (not Adam and Eves) when He said that He'll make a SUITABLE HELPER for Adam. Not Helpers. GENESIS 2:18.

2. Therefore shall a man leave his father and his mother, and shall cleave unto his WIFE (NOT WIVES) and they shall be ONE FLESH. GENESIS 2:24.

3. The Bible says, "he that finds A WIFE, finds a good thing..." we are not advised to find wives. PROVERBS 18:22.

4. Moses the patriarch gave guidelines on qualities that a would-be political leader must possess. Among the prerequisites is that the political leader should not marry many wives. DEUTERONOMY 17:17.

5. In the same vein, Christian leaders are also warned to make sure that a man is not married to more than ONE WIFE before he is ordained or given important religious or spiritual title and or position. 1Timothy 3:2.

6. Jesus Christ will officially marry A WIFE – the Church. Even as the Saints are a multitude of men and women, Jesus Christ still refer to us as WIFE. Meaning that in Heaven polygamy isn't recognised! REVELATION 19:7-9.

7. EPHESIANS 5:23: For the husband is the HEAD of the WIFE, even as Christ is the head of the church. Paul, the learned gentleman is writing to the Christians in Ephesus. Logically, in the context of the above verse, if the husband is the Head of his wife, what is a man who married more than one wife – HEADS?

8. MALACHI 2:15: ...THEREFORE TAKE HEED TO YOUR SPIRIT, AND LET NONE DEAL TREACHEROUSLY AGAINST THE WIFE Of HIS YOUTH. This verse is self explanatory – it means that a man should not cheat on his wife – or have "side chicks".

9. 1 CHRONICLES 14:3 "And David [took more wives] at Jerusalem: and David begat more sons and daughters."
I saw the post of a notable public figure using the above verse in making a case in favour of polygamy in the wake of the news of a popular Nigerian actor taking on a second wife. He cited few other verses to buttress his point.

Look, that David flouted the ordinance of Moses doesn't make him right. The patriarch Abraham married one apparently barren wife, Sarah. Noah married one wife, Isaac one, Jacob only had two wives circumstantially and that was not his original intention. Peter married one wife, Zachariah, the father of John the Baptist, despite his wife's apparent barrenness stuck to only Elisabeth till old age!

Importantly, Mary, the mother of Jesus Christ in the flesh, was the ONLY wife of Papa Joseph.

10. Lastly but not exhaustively, the Book Of Song of Solomon figuratively and sublimely present to us the role-playing of the quintessential union of Holy matrimony. Christ and the Church are personified and deftly represented in metaphors as Husband and Wife – NOT WIVES.

Shalom.

But almost all the prophets in the old testament gets many wives now

If you like marry 20 wives, it still one man one wife