Sec. 122 is a revelation given to Joseph Smith. I can imagine that it gave him a great deal of comfort, while also keeping him humple and aware of things to come.
"...know thou, my son, that all these things shall give thee experience, and shall be for thy good.
"The son of man hath descended below them all. Art thou greater than He?"
"...thy days are known, and thy years shall not be numbered less; therefore, fear not what man can do, forGod shall be with you forever and ever."
Everytime I think my life is hard and I read these verses, I am immediately humbled. Raising young kids is hard? Managing money is hard? Being busy is hard? At least I'm separated from my spouse and my children. At least I'm not unjustly imprisoned. At least I can stand to my full height whenever I want. At least I'm not freezing. At least no one's trying to poison me.
And then on top of this, Joseph is reminded that as bad as all that is, Christ descended even lower.
The next section is a letter that Joseph wrote to the saints as they were being driven from their homes, and he was still imprisoned.
After talking about their duty to spread the gospel throughout the world, he says, "Therefore, dearly beloved brethren, let us cheerfully do all things that lie in our power; and then may we stand still, with the upmost assuarnce, to see the salvation of God, and for his arm to be revealed."
Isn't that a fantastic scripture? What a perfect guideline for enduring our trials, or simply doing what we should be doing. Do it cheerfully, do all you can, then let God do the rest.