They Did Boast in Their Own Strength – Mosiah 11:19

Mormon was familiar with the kind of hubris demonstrated by King Noah’s armies in this passage. After a single victory in battle, Noah’s armies began to boast in an exaggerated manner, claiming that fifty of them could defeat thousands of their enemies. This was absurd, given the fact that they had lost the prior battle because the king “did not send a sufficient number” of soldiers to defeat the enemy (Mosiah 11:17). In other words, they had sufficient empirical data to estimate the manpower required to defend themselves if they had not let pride cloud their judgment. Even before Abinadi arrives in verse 20 to warn them of their imminent destruction, an objective observer can see the writing on the wall. Their pride was leading to their downfall. (See Proverbs 16:18.)
Mormon’s experience was similar. After a series of forced retreats, he led his armies to victory against their enemies:

And now, because of this great thing which my people, the Nephites, had done, they began to boast in their own strength, and began to swear before the heavens that they would avenge themselves of the blood of their brethren who had been slain by their enemies.
And they did swear by the heavens, and also by the throne of God, that they would go up to battle against their enemies, and would cut them off from the face of the land (Mormon 3:9-10).

After seeing this irrational and dangerous reaction among his troops, Mormon resigned his post as their commander, and “did utterly refuse from this time forth to be a commander and a leader of this people” (Mormon 3:11). He later wrote to his son, Moroni, “the pride of this nation, or the people of the Nephites, hath proven their destruction except they should repent” (Moroni 8:27).
Today, I will remember the dangers of overestimating my abilities based on prior successes. I will strive to keep my accomplishments in perspective and to be aware of my limitations, so that I can make wise decisions about how to address the challenges I face, and so that I will be motivated to seek the help I need to be successful.