"All beings who have bodies have power over those who have not. The devil has no power over us only as we permit him." (Joseph Smith, TPJS, Section 4, p. 181)
"Before foundation of the earth in the Grand Council that the spirits of all men were subject to oppression, and the express purpose of God in giving them a tabernacle was to arm them against the power of Darkness." (Joseph Smith, Discourse, [19 January 1841], as Reported by William P. McIntire's Notebook, p. 7)
"God is good and all his acts are for the benefit of inferior intelligences— God saw that those intelligences had not power to defend themselves against those that had a tabernacle therefore the Lord calls them together in council and agrees to form for them tabernacles so that he might gender the spirit and the tabernacle together so as to create sympathy for their fellow man— for it is a natural thing with those spirits that have the most power to bear down on those of lesser power, so we see the devil is without a tabernacle and the Lord has set bands to all spirits." (Ibid. p. 18)
"And the spirit and the body are the soul of man." (D&C 88:15)
"The Father has a body of flesh and bones as tangible as man’s; the Son also; but the Holy Ghost has not a body of flesh and bones, but is a personage of Spirit. Were it not so, the Holy Ghost could not dwell in us." (D&C 130:22)
"Now the Lord had shown unto me, Abraham, the intelligences that were organized before the world was; and among all these there were many of the noble and great ones; And God saw these souls that they were good, and he stood in the midst of them, and he said: These I will make my rulers; for he stood among those that were spirits, and he saw that they were good; and he said unto me: Abraham, thou art one of them; thou wast chosen before thou wast born.
"And there stood one among them that was like unto God, and he said unto those who were with him: We will go down, for there is space there, and we will take of these materials, and we will make an earth whereon these may dwell; And we will prove them herewith, to see if they will do all things whatsoever the Lord their God shall command them; And they who keep their first estate shall be added upon; and they who keep not their first estate shall not have glory in the same kingdom with those who keep their first estate; and they who keep their second estate shall have glory added upon their heads for ever and ever.
"And the Lord said: Whom shall I send? And one answered like unto the Son of Man: Here am I, send me. And another answered and said: Here am I, send me. And the Lord said: I will send the first. And the second was angry, and kept not his first estate; and, at that day, many followed after him." (Abraham 3:22-28)