Ludlow argues that the Jaredites practiced polygamy.
Daniel H. Ludlow, A Companion to Your Study of the Book of Mormon (Salt Lake City: Deseret Book, 1976), 327
ETHER 14:2 Did the Jaredites practice polygamy?
The early Nephite records indicate quite clearly that the Nephites were not to practice polygamy. The prophet Jacob was commanded by the Lord to say to his people: "...there shall not any man among you have save it be one wife." (Jacob 2:27.) However, Jacob later makes it clear that if the Lord wants his people to "raise up seed" unto him, then he might command them to practice polygamy. (Jacob 2:30.) It is not clear, however, whether or not the Jaredites were commanded by the Lord to practice polygamy. The following evidences have been cited which might indicate that they did practice polygamy: (1) Many of the men had large numbers of sons and daughters. For example, the brother of Jared had 22 sons and daughters (Ether 6:20) and Orihah had 31 sons and daughters (Ether 7:2).
(2) Riplakish had "many wives and concubines" (Ether 10:5). He was condemned by the Lord for his wickedness, but it is not clear whether or not this condemnation was because of his "many wives."
(3) Ether 14:2 states that every man kept the hilt of his sword in his right hand, in the defence of his property and his own life and of his wives and children." This verse seems to indicate that the people practiced polygamy, but whether or not it was sanctioned by the Lord is not made clear in the record.