In this chapter Mormon spoke about those in the latter days that will read this account, the Gentiles that care for the house of Israel (baptized members). He said they know where their blessings come from (vs 10). He also said the they will feel sorrow when they read about the destruction of this people.
I've read chapter 4 before, many times. Each time I feel sad. I understand that I sorrow- like he did - because of my testimony of my Savior and my desire for all to come to him, that they may not suffer the consequences of following the Adversary.
Mormon knew it would have this effect, and though sad, it was the desired effect. Hopefully this clear and terrible picture of a fallen people will be enough to bring their posterity back to Christ (v 14).
But he knew this wouldn't be the end of their suffering. He saw that things got much worse, that they were guided by the Adversary, being tossed to and fro. He also saw when they would be scattered by the Gentiles (when the white people took over the land from the Indians, as history would record it).
At the end he asks us a very pointed question: Know ye not that ye are in the hands of God? I love the image that sentence creates. Me, safely nestled in His hands.
He calls on us to humble ourselves. To me, that means submit ourselves to His will. We are in His hands. As described in Jeremiah chapter 18 of the Old Testament, we are clay in the Hands of the Potter. And we are asked to trust Him, that He will make something beautiful out of us- if we let ourselves be mold-able.
Either that, or the seed of Jacob will go forth and tear us into pieces. (v 24)
I choose the potter's hands.