Here are part of King Benjamin’s words about Christ which he shares with his people as they had been given him by an angel:

And he shall rise the third day from the dead; and behold, he standeth to judge the world; and behold, all these things are done that a righteous judgment might come upon the children of men. (Mosiah 3:10)

That bit at the end is intriguing as it suggests that Christ’s atonement and resurrection (which leads to the resurrection of all men) had to happen in order to bring about a righteous judgment on mankind, as if justice would be frustrated otherwise.

In what way would this be the case?

Well, we know that every person becomes spiritually alienated from God from their very first sin committed contrary to their knowledge of the commandments. Without the atonement of Christ, not only would man stay alienated from God, but after death they would never receive their body back, and they would remain cast out of God’s presence, and there would be no chance for additional judgment beyond their first fall.  No final judgment. 

Further, if man happened to do any good works before their fall, he would have no opportunity to be rewarded for those works because the fall would have alienated them from God forever already.

So, the atonement was needed to bring man back into the presence of God for final judgment so that they could receive reward for good works as well as punishment for evil not repented of.  Righteous judgment requires that good be rewarded, not just for evil to be punished.

And the atonement makes it possible for us to do good even after having fallen. 

The thing is, any good we do we owe to God. We would not know what was good without the light of Christ, our conscience within us. We would not know how to improve without revelation to us of the way. We would not have power to overcome the natural man without the enticing of the Holy Ghost.  Everything good about us we owe to God in one way or another. 

It’s taken me a long time to realize that, but I think I’m okay with that.  When I was young, I wanted to be good on my own.  I thought I could be good separate from any help from God.  But the longer I live and learn, the more I see that there’s nothing good in me that I wasn’t given from God, starting with being a child of God with divine potential.  

I’m happy with that because it means I can really depend on God if I let myself.  (The question is if I can keep letting myself.)