Amulek gives us the quintessential passage on the nature and perfection of the resurrected body. Along with the words of Alma which state, The soul shall be restored to the body, and the body to the soul; yea, and every limb and joint shall be restored to its body; yea, even a hair of the head shall not be lost; but all things shall be restored to their proper and perfect frame (Alma 40:23), we are to understand that the Lord will give us an incredible, completely free gift—a completely flawless, perfect, immortal body.
If our goal is to become perfect even as our Father in Heaven is perfect, then one of the most important elements in that quest has been taken care of for us in the great Resurrection. We are to receive a perfect body. This perfect body is to be united with that spirit body which was created in a state of innocence for us in the beginning. In the beginning, our spirit bodies were perfect but they could not remain in innocence as they were all marred by the unrighteous exercise of agency. Therefore, the union of these two bodies, never again to be separated, does not make us perfect. It is not enough. That perfect body will still be controlled by the individual who controlled it in mortality. Amulek later explains, that same spirit which doth posses your bodies at the time that ye go out of this life, that same spirit will have power to possess your body in that eternal world (Alma 34:34). True perfection, then, will depend upon the perfection of the spirit by a) the perfect submission of individual will to the will of the Father, b) the mastery of the spirit of obedience, and c) the cleansing of the inner vessel from all impurities. Otherwise, we will stand before God, with our perfect bodies, having a bright recollection of all our guilt.
Joseph F. Smith
"(speaking of the resurrection) Deformity will be removed; defects will be eliminated, and men and women shall [return] again to the perfection of their spirits, to the perfection that God designed in the beginning. It is his purpose that men and women, his children, born to become heirs of God, and joint heirs with Jesus Christ shall be made perfect, physically as well as spiritually through obedience to the law by which he has provided the means that perfection shall come to all his children." (Joseph Fielding Smith, Answers to Gospel Questions, vol. 4, p. 187)
Joseph Fielding Smith
"A little sound thinking will reveal to us that it would be inconsistent for our bodies to be raised with all kinds of imperfections. Some men have been burned at the stake for the sake of truth. Some have been beheaded, and others have had their bodies torn asunder; for example, John the Baptist was beheaded and received his resurrection at the time of the resurrection of our Redeemer. It is impossible for us to think of him coming forth from the dead holding his head in his hands; our reason says he was physically complete in the resurrection, He appeared to the Prophet Joseph Smith and Oliver Cowdery with a perfect resurrected body." (Doctrines of Salvation, vol. 2, p. 289)
Dallin H. Oaks
"Many living witnesses can testify to the literal fulfillment of these scriptural assurances of the resurrection. Many, including some in my own extended family, have seen a departed loved one in vision or personal appearance and have witnessed their restoration in 'proper and perfect frame' in the prime of life. Whether these were manifestations of persons already resurrected or of righteous spirits awaiting an assured resurrection, the reality and nature of the resurrection of mortals is evident. What a comfort to know that all who have been disadvantaged in life from birth defects, from mortal injuries, from disease, or from the natural deterioration of old age will be resurrected in 'proper and perfect frame.'" (Conference Report, Apr. 2000, May Ensign, p. 15)