Some of you are adulterers and adulteresses.
Whoever looks at a woman with lust has commited adultery in their hearts.
You [Joseph Smith] asked me [God] about adultery. Here is my answer:
If a man receives a wife in the new and everlasting covenant, and if she has sex with another man that I haven't appointed to her, then she has committed adultery and must be killed. 132:41
If she isn't in the new and everlasting covenant and she has sex with another man, she has committed adultery. 132:42