Can you provide the reference for this?
سئل [ابن خزيمة] من أين أوتيت العلم؟ فقال: قال رسول الله – صلى الله عليه وسلم- ماء زمزم لما شرب له وإني لما شربت، سألت الله علما نافع
Answer
‘Allamah Dhahabi, ‘Allamah Subki (rahimahumallah) and others have cited this incident regarding Imam Ibn Khuzaymah (rahimahullah).
(Siyaru A’alamin Nubala, vol. 14 pg. 370, Tabaqatush Shafi’iyyah, vol. 3 pg. 110)
Translation
Imam Ibn Khuzaymah (rahimahullah) was asked, ‘How did you acquire such knowledge’? He replied, ‘Nabi (sallallahu ‘alayhi wa sallam) said, ‘Zamzam is [suitable] for whatever purpose it is drank for‘. So when I drank Zamzam, I asked Allah Ta’la to bless me with beneficial knowledge’
And Allah Ta’ala Knows best.
Answered by: Moulana Suhail Motala
Approved by: Moulana Muhammad Abasoomar
Checked by: Moulana Haroon Abasoomar