It is narrated from Hazrat Ibn Abbas (may Allah be pleased with them both) with reference to Ubayy bin Ka'b (may Allah be pleased with him) that when Hazrat Jibreel (peace be upon him) struck his heel and caused the well of Zamzam to flow, the mother of Hazrat Ismail (peace be upon him) began gathering pebbles to make a boundary. The Noble Prophet (peace and blessings be upon him) said: "May Allah's mercy be upon Hajrah (peace be upon her), who was the mother of Hazrat Ismail (peace be upon him). If she had left it as it was, it would have become a flowing stream."