Sahih Bukhari Volume 004, Book 055, Hadith Number 582.
Narated By Ibn 'Abbas : The Prophet said, "May Allah bestow His Mercy on the mother of Ishmael! Had she not hastened (to fill her water-skin with water from the Zam-zam well). Zam-zam would have been a stream flowing on the surface of the earth." Ibn 'Abbas further added, "(The Prophet) Abraham brought Ishmael and his mother (to Mecca) and she was suckling Ishmael and she had a water-skin with her.'