2 Nephi 9:11

And because of the way of deliverance of our God, the Holy One of Israel, this death, of which I have spoken, which is the temporal, shall deliver up its dead; which death is the grave.

Because our God, the Holy One of Israel, gives us a way to be saved, this death will give back the dead bodies. This is the grave.

Because of what God has done—the Holy One of Israel—physical death will give up its dead. The grave will open.