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