2 Samuel 17:17-18

17Jonathan and Ahimaaz were waiting at En Rogel. They could not risk being seen coming into the city, so a servant girl was to go and tell them, and they were to go and tell King David.

18But a young man saw Jonathan and Ahimaaz and told Absalom. So both of them left quickly and came to the home of a man in Bahurim who had a cistern in his courtyard, and they went down into it.