Explaining the origin of Zamzam Ibn ‘Abbas said: “When Hajar reached the (mountain) of Marwah in search of water for her baby son Isma’il and herself to quench their thirst. she heard a sound, and said to herself, “Quiet.” She again heard the sound, whereupon she said, “I have heard you. Help me, if you can.” All of a sudden she found an angel at the place where now Zamzam is. He either dug it with his heel or touched it (the ground) with his wing and a spring of water appeared. Hajar encircled the water with soil. She took some water in a container she had, and water kept bubbling up unchecked.”

Ibn ‘Abbas reported that the Prophet (peace be upon him) said, “‘May Allah shower His mercy on Isma’il’s mother. Had she left it untouched, or (the narrator is not sure) the Prophet said, had she not drunk of its water, the Zamzam would have turned into a clear flowing spring.’ He added, ‘So she drank the water and gave some to her son.’ The angel said to her, ‘Fear no loss because this is the site of Allah’s House, which this boy and his father shall build. Allah never permits His servant to be lost. At the site of the House was a hill that was split by flood waters running down its right and left.”‘

Fiqh 5.82