The third scripture mastery is 2 Nephi 2:25. "Adam fell that men might be; and men are, that they might have joy."
Application to my life: Because Adam fell, we were all able to come to earth and experience trials and sadness but also blessings and joy. With out knowing difficulties in life and sadness, we never would experience the blessings we get from overcoming those trials and joy of succeeding. If life was always perfect, how would there be joy? You would be the same everyday and not experiencing anything different. I am thankful for the hard times I've been through and been able to grow and experience the joy of overcoming those difficult times.