Just before David left Saul's service for the last time, he and Jonathan arraigned a way to communicate with one another in code:
Jonathan, out of his love for David, adjured him again, for he loved him as himself. Jonathan said to him, “Tomorrow will be the new moon; and you will be missed when your seat remains vacant. So the day after tomorrow, go down all the way to the place where you hid the other time, and stay close to the Ezel stone. Now I will shoot three arrows to one side of it, as though I were shooting at a mark, and I will order the boy to go and find the arrows. If I call to the boy, ‘Hey! the arrows are on this side of you,’ be reassured and come, for you are safe and there is no danger—as the Lord lives! But if, instead, I call to the lad, ‘Hey! the arrows are beyond you,’ then leave, for the Lord has sent you away. As for the promise we made to each other, may the Lord be [witness] between you and me forever.”—1st Samuel 20:17-23 (NJPS)
But after they execute their plan, they end up meeting with one another directly:
The boy suspected nothing; only Jonathan and David knew the arrangement.—Jonathan handed the gear to his boy and told him, “Take these back to the town.” When the boy got there, David emerged from his concealment at the Negeb. He flung himself face down on the ground and bowed low three times. They kissed each other and wept together; David wept the longer.
Jonathan said to David, “Go in peace! For we two have sworn to each other in the name of the Lord: ‘May the Lord be [witness] between you and me, and between your offspring and mine, forever!’”—1st Samuel 20:39-42 (NJPS)
If David and Jonathan are able to meet even when Saul is in a rage against both of them for friendship, what was the purpose of setting up the arrow signal?