According to Mormon doctrine, body and spirit combined constitute a soul. Every man and woman that has ever lived on earth, previously lived as a spirit in the preexistence, and was born to earth into a mortal body prepared by mortal parents. Our mortal bodies are frail, and eventually die, at which point our spirits are separated from them until the resurrection.
I remember learning about body and spirit as a child, when our Sunday school teachers would explain that our bodies were like a glove, and our hands like our spirit. When the hand is in the glove it gives the glove life, but when we take it out, then the glove dies. After the resurrection, our spirits are reunited with our bodies, but cannot die again meaning that they are forever thereafter inseparable (see Romans 6:9).
According to Mormon Doctrine, What happens to our spirit and body during the resurrection that makes them inseparable?