A fourth method used by Smith was-the angel will slay me with a sword if you don't accept my proposal.

Smith sent a message in October 1841 to Zina Huntingon Jacobs, declaring that an angel with a drawn sword had stood over him, telling him that if he did not establish polygamy-he would lose "his position and his life."

Faced with such a responsibility, Zina finally acquiesced.[64]

Mary Rollins Lightner, also a married woman, said Smith used the same approach on her in February 1842.
He informed Mary, "The angel came to me three times between the year of '34 and '42 and said I was to obey that principle or he would [s]lay me."[65]

Clearly, Joseph Smith has little regard for the tenth commandment-"Thou shalt not covet they neighbour's wife" (Exodus 20:17).

http://mormonthink.com/grant6.htm