Nowadays they don't practice but their holy books some prophets are polygamist
By and large modern Judaism and modern Christianity do not promote polygamy, but historically both did. In either case, the two religions are similar in this respect.
Christianity, Judaism, Islam and Bahai.
Judaism - the 'parent' religion of Christianity.
The main three would be Judaism, Christianity, and Islam.
Approximately 84% of the world's population live in countries where polygamy is legally recognized or has a cultural acceptance. However, the actual percentage of people practicing polygamy is estimated to be lower, with around 2% to 5% of men worldwide involved in polygamous relationships.
Christianity and Judaism
Islam, Judaism and Christianity.
Groups of Mormons that have splintered from The Church of Jesus Christ of Latter Day Saints allow polygamy. The main body of the church is in no way connected to what are called "Mormon Fundamentalists" and does not practice polygamy. Polygamy (specifically Polygyny or one man having more than one wife) is also permitted in most forms of Islam.
no where in the US is it legal to practice polygamy
The significance is that it became the foundation of modern Judaism, Islam, and Christianity.
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The Pope has called Judaism "Christianity's older sister," since Christianity bases much of its content on Judaism.