Bear one another's burdens
That they may be light.
Mourn with those that mourn.
Comfort those that stand in need of comfort.
In the tradition of Mormon poets like William W. Phelps and Orson F. Whitney I have made my paraphrasing of Mosiah 18: 8-9 into a kind of mantra. It's very important doctrine because it's part of my covenant with God from my baptism. What I really love about this is the special kind of intimacy and deep friendship that comes from sharing burdens, mourning together. This is one of the most Christ-like, God-like things I can imagine.
Real friendship is proven in hard times. Friends have fun together, play together and laugh together. But they should also cry together and struggle together. And the blessing is imbedded right there in the counsel: bear one another's burdens that they may be light. Just sharing the burden helps.
There are a lot of burdens to be shared and made light. In the words of Jeffy R. Holland: “We have neighbors to bless, children to protect, the poor to lift up, and the truth to defend. We have wrongs to make right, truths to share, and good to do. In short, we have a life of devoted discipleship to give in demonstrating our love of the Lord. We can’t quit and we can’t go back." 
So I repeat the mantra from Mosiah 18:8-9 regularly to keep my mind and heart right with God. This is what we need to do.