Meaning
It was at this fountain that Jonathan and Ahimaaz lay hid after the flight of David (2Sam 17:17); and here also Adonijah held the feast when he aspired to the throne of his father (1Kings 1:9).
The Bir Eyub, or "Joab's well," "is a singular work of ancient enterprise. The shaft sunk through the solid rock in the bed of the Kidron is 125 feet deep...The water is pure and entirely sweet, quite different from that of Siloam; which proves that there is no connection between them." Thomson's Land and the Book.