"You are aware that many think the devil has power over both the body and spirit. Now I want to tell you that he does not hold power over any, only as far as the body overcomes the spirit that is in man, through yielding to the spirit of evil. The spirit that the Lord puts into a tabernacle of flesh is under the dictation of the Lord Almighty…In the first place the spirit is pure, and under the special control and influence of the Lord, but the body is of the earth, and is subject to the power of the devil, and is under the mighty influence of that fallen nature that is of the earth. If the spirit yields to the body, the devil then has power to overcome the body and spirit of man, and [that man] loses both…When you are tempted, buffeted, and step out of the way inadvertently: when you are overtaken in fault, or commit an over act unthinkingly; when you are full of evil passion and wish to yield to it, then stop and let the spirit, which God has put into your tabernacles, take the lead. If you do that, I promise that you will overcome all evil, and obtain eternal lives. But many, very many, let the spirit yield to the body and are overcome and destroyed."
Brigham Young, Journal of Discourses 2:256 (emphasis added)