Question: What does it mean to “cross yourself” in all these things?
Answer: The expression cross yourself means to “deny yourself.” Corianton was advised by his father Alma to “cross yourself” or deny yourself “the lust of your eyes.” Corianton followed the advice of his father and repented of past wrongs.
“Now my son, I would that ye should repent and forsake your sins, and go no more after the lusts of your eyes, but cross yourself in all these things; for except ye do this ye can in nowise inherit the kingdom of God. Oh, remember, and take it upon you, and cross yourself in these things” (Alma 39:9).
Source: 400 Questions and Answers About the Book of Mormon by Susan Easton Black, p. 163.