Amulek gives us the quintessential passage on the nature and perfection of the resurrected body, The spirit and the body shall be reunited again in its perfect form; both limb and joint shall be restored to its proper frame, even as we now are at this time…and even there shall not so much as a hair of their heads be lost; but every thing shall be restored to its perfect frame (Alma 11:43-44). From this we are to understand that the Lord will give us an incredible, 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 has had its rest in the world of spirits.
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)
David O. McKay
"The question frequently arises as to whether a child that died in infancy will remain a child in the hereafter, and whether in the resurrection the spirit will take up the same body that it tabernacled in the flesh.
"The doctrine of the Church in this respect was very clearly set forth by the late President Joseph F. Smith in an editorial in The Improvement Era, June 1904, wherein he stated, ’The body will come forth as it is laid to rest, for there is no growth or development in the grave. As it is laid down, so will it arise, and changes to perfection will come by the law of restitution. But the spirit will continue to expand and develop, to the full stature of man.’
"Parents, therefore, who have been parted from their children by death may rest assured that, if worthy through obedience to the principles of the gospel, they will not only meet their children in the spirit world, but will also recognize them and know them as they knew them in this life. Parents, too, have even a greater comfort in the fact that their little ones whose lives on earth were cut short will continue to grow and develop, and receive every blessing to which their inheritance and faithfulness will entitle them. (Gospel Ideals, p. 75 as taken from Latter-day Commentary on the Book of Mormon compiled by K. Douglas Bassett, p. 340)