Braden Scothern answered...

At many times in the Bible prophets were commanded to practice polygamy. Some of these prophets were Abraham, Isaac, Jacob, Moses, David, and Solomon.

We know that plural marriage is a sin unless God commands us to practice it. In the Book of Mormon the prophet Jacob tells the Lords will on the subject, “for there shall not any man among you have save it be one wife: and concubines he shall have none... for if I will, saith the Lord of Hosts, raise up seed unto me, I will command my people; otherwise they shall hearken unto these things” (Jacob 2:27-30).

So only as the Lord commands His people is it acceptable. While they early saints accepted this it was not an easy commandment to keep. They had many struggles with it and only under the direction of the Lord was it carried out. The Church leaders closely supervised the practice and only those who had been authorized by the Lord were to practice. In addition to that all of the marriages had to be performed by the sealing power of the priesthood which had been restored. It was not a temporary thing when it was practiced.

In 1890, President Woodruff received revelation that plural marriage was no longer acceptable to the Lord. So the practice was stopped instantly. Anyone who practices polygamy now is NOT a member of the Church of Jesus Christ of Latter-day Saints.