I teach the people correct principles and they govern themselves. - Joseph Smith

Element had an existence from the time he [God] had. The pure principles of element are principles which can never be destroyed; they may be organized and re-organized, but not destroyed. They had no beginning, and can have no end. . . . [T]he mind of man — the immortal spirit. Where did it come from? All learned men and doctors of divinity say that God created it in the beginning; but it is not so: the very idea lessens man in my estimation. I do not believe the doctrine; I know better. Hear it, all ye ends of the world; for God has told me so . . . We say that God himself is a self-existent being. Who told you so? It is correct enough; but how did it get into your heads? Who told you that man did not exist in like manner upon the same principles? Man does exist upon the same principles. God made a tabernacle and put a spirit into it, and it became a living soul. . . . The mind or the intelligence which man possesses is [co-eternal] with God himself. I know that my testimony is true . . . Is it logical to say that the intelligence of spirits is immortal, and yet that it had a beginning? The intelligence of spirits had no beginning, neither will it have an end. That is good logic. That which has a beginning may have an end. There never was a time when there were not spirits; for they are [co-eternal] with our Father in heaven. . . . I take my ring from my finger and liken it unto the mind of man—the immortal part, because it has no beginning. Suppose you cut it in two; then it has a beginning and an end; but join it again, and it continues one eternal round. So with the spirit of man. As the Lord liveth, if it had a beginning, it will have an end. All the fools and learned and wise men from the beginning of creation, who say that the spirit of man had a beginning, prove that it must have an end; and if that doctrine is true, then the doctrine of annihilation would be true. But if I am right, I might with boldness proclaim from the house-tops that God never had the power to create the spirit of man at all. God himself could not create himself.

Doctrine and Covenants, 135:4 (22 June 1844)

One of the grand fundamental principles of Mormonism is to receive truth, let it come from whence it may.