Verse 13 confirms Mormon’s application of the negative consequence of Lehi’s promise. The destruction of the Nephites does not come because of any change in military equipment or prowess, but because they have lost the special protection of God. When God removed his protection, they were “left in their own strength.” As in past conflicts, the Lamanites were doubtless superior in number, and now that superiority was able to become overwhelming because God was no longer their to counteract the Lamanite strength. Of course God’s absence was not God’s choice, but the natural application of the negative aspect of the promise. When the people no longer were righteous, God could no longer protect them, and their right to safety in the promised land was revoked.