The bible teaches that it is lawful and not a sin to marry multiple wives and concubines. As Christians we are called to be more like Christ who describes himself marrying five virgins at once in the parables and a polygynous spiritual marriage with his ecclesia.
The church has completely twisted the institution of marriage into the Greeco-Roman tradition of monogamy, which traditionally also allowed men to have mistresses and prostitutes.
According to the bible, it is not adultery if a married man sleeps with a single woman. But to avoid fornication (sex without intention of marriage) the bible says he must pay 50 shekels of silver to her father and marry her while still remaining married to his first wife, whom he would not be allowed to divorce.
The only reason the law would be structured like that is to allow polygyny. If the God of the bible wanted monogamy it would be specified in the law but nowhere in scripture is polygyny condemned.
The church rely on only two scriptures out of context Matthew 19:5 and 1 Corinthians 7:2 to justify monogamy.
The first is about divorce and the one flesh union. "The two shall become one-flesh" is used to justify monogamy but the bible also teaches that a man also becomes one flesh with a prostitute if he has sex with her. So that represents any sexual union rather than a wedding ceremony. And there is no prohibition on a man having multiple one-flesh unions. But as Jesus describes there is a prohibition on divorce except when the woman commits adultery.
And the second scripture is promoting marriage to avoid fornication. It says a man should have a wife but a woman should have only one husband. In the context it is saying it's better to have a wife rather than no wife and be doing fornication. But it again doesn't specifically say one wife when it does say one husband. Having additional wives was common in the Jewish tradition.
Jesus said he came not to destroy the law of Moses and not one jot nor tittle would pass from it until the end of the Millennial Kingdom. That means plural marriage is allowed for christian men today.
Take multiple wives, be fruitful and multiply. Take maid, servants and concubines into yur house. Provide a refuge for travellers. Heal the sick, give to the poor, visit those in prison. Raise livestock and build a homestead and your very own kingdom!