Man who defends polygamy is a idiot in using the Bible to defend himself to do such. For Jacob only acknowledged Leah as his wife in his dieing bed, and not the others. And also he only acknowledged Sarah as Abraham's wife and not Hagar.

Genesis 49:29-31
Then he charged them and said to them: “I am to be gathered to my people; bury me with my fathers in the cave that is in the field of Ephron the Hittite, in the cave that is in the field of Machpelah, which is before Mamre in the land of Canaan, which Abraham bought with the field of Ephron the Hittite as a possession for a burial place.There they buried Abraham and Sarah his wife, there they buried Isaac and Rebekah his wife, and there I buried Leah.

In Abraham taking Hagar as his wife he did so in disobedience to God for we see what God opinion was on the matter.

Genesis 21:10-12
Therefore she ( Sarah) said to Abraham, “Cast out this bondwoman and her son; for the son of this bondwoman shall not be heir with my son, namely with Isaac.” And the matter was very displeasing in Abraham’s sight because of his son. But God said to Abraham, “Do not let it be displeasing in your sight because of the lad or because of your bondwoman. Whatever Sarah has said to you, listen to her voice; for in Isaac your seed shall be called.

Galatians 4:30 Nevertheless what does the Scripture say? “Cast out the bondwoman and her son, for the son of the bondwoman shall not be heir with the son of the freewoman.”

Kings where warn not to multiply in having wives because of that thier heart would turn away from following God.

Deuteronomy 17:17
Neither shall he multiply wives for himself, lest his heart turn away; nor shall he greatly multiply silver and gold for himself.

Which we see such in Solomon who had multiple wives because of that departed from following God.

1 Kings 11:3-4
And he had seven hundred wives, princesses, and three hundred concubines; and his wives turned away his heart. For it was so, when Solomon was old, that his wives turned his heart after other gods; and his heart was not loyal to the Lord his God, as was the heart of his father David.

Elkanah had problems among his wives getting along. For one made fun of the other for not being able to give birth.

1 Samuel 1:1-2,4-8 Now there was a certain man of Ramathaim Zophim, of the mountains of Ephraim, and his name was Elkanah the son of Jeroham, the son of Elihu, the son of Tohu, the son of Zuph, an Ephraimite. And he had two wives: the name of one was Hannah, and the name of the other Peninnah. Peninnah had children, but Hannah had no children. And whenever the time came for Elkanah to make an offering, he would give portions to Peninnah his wife and to all her sons and daughters. But to Hannah he would give a double portion, for he loved Hannah, although the Lord had closed her womb. And her rival also provoked her severely, to make her miserable, because the Lord had closed her womb.So it was, year by year, when she went up to the house of the Lord, that she provoked her; therefore she wept and did not eat. Then Elkanah her husband said to her, “Hannah, why do you weep? Why do you not eat? And why is your heart grieved? Am I not better to you than ten sons?”

And in the New Testament Jesus narrows down marriage to one man and one woman.

Matthew 19:4-6
And He answered and said to them, “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.”

And Bishops are told to be the husband of only one wife .

1 Timothy 3:1-2
This is a faithful saying: If a man desires the position of a bishop, he desires a good work. A bishop then must be blameless, the husband of one wife, temperate, sober-minded, of good behavior, hospitable, able to teach;

Which by the way , how is a bishop to lead not by commanding as a king would do to his peasants but as an example to others which means them being the Husband of one wife should lead to others to do the same.

1 Peter 5:1-3
The elders who are among you I exhort, I who am a fellow elder and a witness of the sufferings of Christ, and also a partaker of the glory that will be revealed: Shepherd the flock of God which is among you, serving as overseers, not by compulsion but willingly, not for dishonest gain but eagerly; nor as being lords over those entrusted to you, but being examples to the flock;

Jesus is said to have only one bride who is the church not multiple.

Revelation 21:9 Then one of the seven angels who had the seven bowls filled with the seven last plagues came to me and talked with me, saying, “Come, I will show you the bride, the Lamb’s wife.”

Even among Rabbis the topic of polygamy was rejected among them because none of the ones who is named in Talmud had polygamous relationships and by the 4th and 5th Century it was spoken against.

Rabbi Gershom ben Yehuda banned the practice completely for Ashkenazi Jews in the 10th century.

Sanhedrin 76b
The William Davidson Talmud(Koren - Steinsaltz)

One who loves his wife as he loves himself, and who esteems her by giving her clothing and jewelry more than he esteems himself, ....... Concerning him the verse states: “And you shall know that your tent is in peace; and you shall visit your habitation and shall miss nothing”

Look at what this passage states to love your wife as you love yourself, you can't be loving a person in that matter if you are loving more than one.

This reminds me of what Paul states in Ephesians and again we are told that the two will be one flesh.

Ephesians 5:28-33
So husbands ought to love their own wives as their own bodies; he who loves his wife loves himself.For no one ever hated his own flesh, but nourishes and cherishes it, just as the Lord does the 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. Nevertheless let each one of you in particular so love his own wife as himself, and let the wife see that she respects her husband.