The friendship between David and Jonathan is one of the great friendships in all of literature. I don't mean that David and Jonathan were fictional characters like Sam and Frodo, or Holmes and Watson. But I do mean that in the annals of all writing, whether fiction or non-fiction, the story of these two souls knit together in friendship (1 Sam. 18:1) is truly exemplary.
This friendship was tested by the hatred Jonathan's father had for David. In 1 Samuel 19, Jonathan reasoned with his father, convincing him that David was a hero, not a traitor. Saul agreed - but in one of his characteristic moments of weakness and vacillation, he quickly turned against David once more.
This makes the story in 1 Samuel 20 even more tragic, and poignant. David asks Jonathan why his father seeks to kill him, and Jonathan can't believe this is the case (v. 1-2). It would be hard to accept the fact that your own father is a paranoid maniac, especially when you think you have changed his mind. But as the story in 1 Samuel 2o goes on to explain, Saul did indeed want to murder David - and when Jonathan spoke up for David, Saul tried to kill him! (1 Sam. 20:33). Jonathan got the point (hardee-har-har).
What I love most about Jonathan is his humility. No one stood to lose more by David's kingship than Jonathan. He was the heir to the throne, his father's natural successor (a fact Saul angrily reminded him of in 1 Sam. 20:31). But Jonathan remained ever loyal to David, willing to serve by his side because he knew it was God's will for David to be king (1 Sam. 23:17).
Jonathan was a true friend. He remained loyal to David even at the expense of his father's resentment, and even at the cost of his own status. And despite Saul's failings, he remained loyal to his father, dying at his father's side in battle (1 Sam. 31). We would all be blessed to have a friend in our life with the integrity, courage, and loyalty of Jonathan.