Helaman 12:8-23

For behold, the dust of the earth moveth hither and thither, to the dividing asunder, at the command of our great and everlasting God. Yea, behold at his voice do the hills and the mountains tremble and quake. And by the power of his voice they are broken up, and become smooth, yea, even like unto a valley. Yea, by the power of his voice doth the whole earth shake; Yea, by the power of his voice, do the foundations rock, even to the very center. Yea, and if he say unto the earth—Move—it is moved. Yea, if he say unto the earth—Thou shalt go back, that it lengthen out the day for many hours—it is done; And thus, according to his word the earth goeth back, and it appeareth unto man that the sun standeth still; yea, and behold, this is so; for surely it is the earth that moveth and not the sun. And behold, also, if he say unto the waters of the great deep—Be thou dried up—it is done. Behold, if he say unto this mountain—Be thou raised up, and come over and fall upon that city, that it be buried up—behold it is done. And behold, if a man hide up a treasure in the earth, and the Lord shall say—Let it be accursed, because of the iniquity of him who hath hid it up—behold, it shall be accursed. And if the Lord shall say—Be thou accursed, that no man shall find thee from this time henceforth and forever—behold, no man getteth it henceforth and forever. And behold, if the Lord shall say unto a man—Because of thine iniquities, thou shalt be accursed forever—it shall be done. And if the Lord shall say—Because of thine iniquities thou shalt be cut off from my presence—he will cause that it shall be so. And wo unto him to whom he shall say this, for it shall be unto him that will do iniquity, and he cannot be saved; therefore, for this cause, that men might be saved, hath repentance been declared. Therefore, blessed are they who will repent and hearken unto the voice of the Lord their God; for these are they that shall be saved.

God has power over all physical creation and all the elements. Man also has limited power over physical elements,  but man's power is different from God's. Man's power depends on force and coercion.  Man can move a mountain,  but it takes time, physical exertion, tools, machinery, and explosives. God moves the mountain by his word alone. His voice is sufficient. He speaks his will and the elements obey. They move of their own accord without coercion or compulsion. Whatever man can do, God can do better, bigger, faster, easier, and he has done it first.

At the end of this long list of powers is the one power that man cannot emulate or usurp.  That is God's power to save us. God may delegate many powers to man through the priesthood, including the power to seal up into eternal life, but only God can grant eternal life. Only he can save our immortal souls through the atonement of Jesus Christ.