In the Premortal Realm, Spirit Sons & Daughters Knew & Worshipped God as their Eternal Father & Accepted His Plan by which His Children could obtain a Physical Body & gain Earthly Experience to Progress Toward Perfection & ultimately realize their Divine Destiny as Heirs of Eternal Life.

"Our physical bodies make possible a breadth, a depth, and an intensity of experience that simply could not be obtained in our premortal estate. President Boyd K. Packer, President of the Quorum of the Twelve Apostles, has taught, “Our spirit and our body are combined in such a way that our body becomes an instrument of our mind and the foundation of our character.” Thus, our relationships with other people, our capacity to recognize and act in accordance with truth, and our ability to obey the principles and ordinances of the gospel of Jesus Christ are amplified through our physical bodies. In the classroom of mortality, we experience tenderness, love, kindness, happiness, sorrow, disappointment, pain, and even the challenges of physical limitations in ways that prepare us for eternity. Simply stated, there are lessons we must learn and experiences we must have, as the scriptures describe, “according to the flesh” (1 Nephi 19:6; Alma 7:12–13)." -David A. Bednar, Things as They Really Are 

“We came to this earth that we might have a body and present it pure before God in the celestial kingdom. The great principle of happiness consists in having a body. The devil has no body, and herein is his punishment. He is pleased when he can obtain the tabernacle of man, and when cast out by the Savior he asked to go into the herd of swine, showing that he would prefer a swine’s body to having none. All beings who have bodies have power over those who have not. …The devil has no power over us only as we permit him; the moment we revolt at anything which comes from God, the devil takes power.” -Joseph Smith

Scriptures:

The Spirit itself beareth witness with our spirit, that we are the children of God: And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together. -Holy Bible, Romans 8:16-17

Beloved, now are we the sons of God, and it doth not yet appear what we shall be: but we know that, when he shall appear, we shall be like him; for we shall see him as he is. -Holy Bible, 1 John 3:2

And now, because of the covenant which ye have made ye shall be called the children of Christ, his sons, and his daughters; for behold, this day he hath spiritually begotten you; for ye say that your hearts are changed through faith on his name; therefore, ye are born of him and have become his sons and his daughters. And under this head ye are made free, and there is no other head whereby ye can be made free. There is no other name given whereby salvation cometh; therefore, I would that ye should take upon you the name of Christ, all you that have entered into the covenant with God that ye should be obedient unto the end of your lives. -Book of Mormon, Mosiah 5:7-8

Definitions:

realm - kingdom, sphere, domain
knew - to be acquainted with; to be aware of the truth or factuality of
worshipped - reverence offered to a divine being;
plan - method for achieving an end; goal
experience - direct observation of or participation in events as a basis of knowledge; the conscious events that make up a person's life
progress - a forward or onward movement; goal; advance; gradual betterment
perfection - freedom from fault or defect; flawlessness; maturity; the quality or state of being saintly
heirs - one who inherits or is entitled to succeed to a hereditary rank, title, or office; one who receives or is entitled to receive some endowment or quality from a parent or predecessor