from Wiki on FLDS
Distinctive Doctrines FLDS

"Plural marriage and the law of placing

The FLDS Church teaches the doctrine of plural marriage, which states that a man having multiple wives is ordained by God and is a requirement for a man to receive the highest form of salvation. It is generally believed in the church that a man should have a minimum of three wives to fulfill this requirement.[44] Connected with this doctrine is the concept that wives are required to be subordinate to their husbands.

The church currently practices the law of placing, whereby a young woman of marriageable age is assigned a husband by revelation from God to the leader of the church, who is regarded as a prophet.[45] The prophet elects to take and give wives to and from men according to their worthiness."