In Mark 4:35-41, Jesus teaches us that although following him doesn't exempt us from the storms of life, we can trust him because he is Lord over every storm and is with us in the midst of it.
In 1 Samuel 17:31-58, the Lord vindicates his own name by securing the salvation of his people through his anointed king so that all the earth may know that he alone is God, which points forward to Jesus Christ, the true and better David, whose victory over sin and death became his people's victory, though we did nothing to accomplish it ourselves.