It is possible that there were certain channels of communication whereby David shared details of his whereabouts with those that he considered to be friendly toward him. Knowing who these people were, Jonathan would have approached them for help to find David. Alternatively, Jonathan was a good tracker and able to locate David on his own initiative. In either case, it would have been dangerous for Jonathan to come out and visit David. He would have had to do so in secret.1
16 And Jonathan, Saul’s son, rose and went to David at Horesh, and strengthened his hand in God.