I would like to point out that Abraham, Isaac, and Jacob lived 400-500 years before Moses wrote down the law (dictated by God Himself) that forbids a man from taking more than one wife. Since that time, marriage is between one man and one woman; no exception was written into the law for Joseph Smith, or any of his followers. This is a commandment of God, and no matter how often this law is broken, each and every time it is broken it is still a sin.
the law (dictated by God Himself) that forbids a man from taking more than one wife.