1 Samuel 17:32

And David said to Saul, Let no man’s heart fail because of him; thy servant will go and fight with this Philistine.

David himself volunteers to go and fight the Philistine. In doing so he tells Saul that no man's heart should fail or lose courage because of Goliath, answering the fear that had settled over Israel. His confident offer stands in contrast to Saul's fear and the helplessness of the army before the champion.

His confidence rests on trust that God can help and deliver Israel, not on his own youth and strength and not on human strength and prepared weapons. He is moved to act by zeal to defend the honor of God and to protect Israel from the Philistine's defiance. That trust rests on past experience, for the Lord who had delivered him from a lion and a bear would deliver him again.

He refuses to be overcome by the danger, and his faith and courage enable him to defeat the Philistine champion. His example teaches those who defend God's truth to act with humility, trusting God to give the victory rather than boastfully relying on their own arguments and abilities.