Have you ever considered how David and some events in his life looked forward to Jesus and some of His work?
“David’s struggle with Goliath answers to Christ’s struggle with Satan. In both cases, it was the enemy’s own weapon which was used to destroy him (Hebrews 2:14). Both David and Christ were sent by their father with a message to the brethren. Both were rejected. David was, in a sense, a mediator between the lines of Israel and the Philistines; Christ is the one Mediator between God and man (1 Timothy 2:5).”
–Coffman’s commentary on the NT, Mt. 1