In 1 Samuel 20, Jonathan shows us what it looks like to remain faithful to God’s anointed King even when that allegiance is costly, while David’s covenant faithfulness points us to Christ, whose covenant love gives us security in the midst of uncertainty and frees us to follow him at any cost.
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.