Al-Kāfi - The Book of Drinks

Chapter: Excellence of the Water of Zamzam and the Water of al-Mizab وَ بِإِسْنَادِهِ قَالَ ذُكِرَتْ زَ٠ُ عِنْدَ أَبِي عَبْدِ اللَّهِ ( عليه السلا٠) فَقَالَ أُجْرِيَ إِلَيْهَا عَيْنٌ ٠ِنْ تَحْتِ الْحِجْرِ فَإِذَا غَلَبَ ٠َاءُ الْعَيْنِ عَذُبَ ٠2.

Through the same chain of narrators as that of the previous Hadith, the following is narrated: “Once, Zamzam was mentioned before abu ’Abd Allah (a.s.). He (the Imam) said, ’A fountain from under the stone was made to flow on it. When the water of the fountain overwhelms it, water of Zamzam becomes sweet.’” رسل - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (2/237))