1) David expresses confidence that he will see God's goodness in this life, not just in the afterlife. While this life has trials, God is good and his goodness should be seen in both this world and the next.
2) A story is told of a minister visiting an old saint on his deathbed who said he was in "the land of the dying," not the living. David, however, had hope of experiencing God's goodness in this life.
3) God's goodness is seen through his giving and forgiving nature, even when we are disobedient. His goodness exceeds our sin.