Mosiah 15:20

But behold, the bands of death shall be broken, and the Son reigneth, and hath power over the dead; therefore, he bringeth to pass the resurrection of the dead.

Death’s power will be broken. The Son rules and has power over the dead. So he will bring the dead back to life.

“But death’s chains will be broken! The Son rules over death itself. That’s why he can raise the dead.