The Faithful To Receive Celestial Rest

Here, then, we have this part of our subject immediately before us for consideration: God has in reserve a time, or period appointed in His own bosom, when He will bring all His subjects, who have obeyed His voice and kept His commandments, into His celestial rest. This rest is of such perfection and glory, that man has need of a preparation before he can, according to the laws of that kingdom, enter it and enjoy its blessings. This being the fact, God has given certain laws to the human family, which, if observed, are sufficient to prepare them to inherit this rest. This, then, we conclude, was the purpose of God in giving His laws to us: If not, why, or for what were they given? If the whole family of man were as well off without them as they might be with them, for what purpose or intent were they ever given? Was it that God wanted to merely show that He could talk? It would be nonsense to suppose that He would condescend to talk in vain: for it would be in vain, and to no purpose whatever (if the law of God were of no benefit to man): because, all the commandments contained in the law of the Lord, have the sure promise annexed of a reward to all who obey, predicated upon the fact that they are really the promises of a Being who cannot lie, One who is abundantly able to fulfill every tittle of His word: and if man were as well prepared, or could be as well prepared, to meet God without their ever having been given in the first instance, why were they ever given? for certainly, in that case they can now do him no good.   
   (Joseph Smith, Teachings of the Prophet Joseph Smith, selected and arranged by Joseph Fielding Smith, p.54)