Repentance is a condition for baptism, and ultimately of conversion and salvation. It is also a lifelong process—one never stops needing to repent.
The proof that a person has truly made a change of heart appears when his life begins to show him doing what is right. Right living is the fruit of repentance.
Book II of the Psalms was written largely by David and shows how he reacts to some gruesome trials by surrendering to God's redemption.
Affliction is a necessary aspect of life, yielding strength of character, while ease and comfort weaken us. Christ was perfected as High Priest through suffering.
A great impediment to overcoming our sins is self-justification. We tend to excuse ourselves for what we do, and this only makes it harder to become like God.
Everything about the Priesthood of Christ is superior to the Levitical system, which only served as a type of the access to God that Jesus would fulfill.