Let me remind you of the events it records. King Saul, afflicted by spells of melancholy, and full of jealousy of the young David who, he suspected, would succeed him, had it in his mind to kill him. Saul's son, Jonathan, who had a deep affection and loyalty towards David, arranged to give David a signal if it appeared that his father intended his death. When the matter turned out as expected, the two friends parted, never to see each other again. The story is simple enough, but it is told in the Bible in a manner which makes it immortal.
Several lessons stand out from the story as told in the Bible.
The first is that of loyalty. Jonathan was placed in a difficult situation. He felt loyalty towards his friend, loyalty towards his father. He discharged both duties. He defended his friend as far as he was able, and when he could do no more, he arranged for his escape.