Narrated Abu Huraira: Allah's Apostle said, "Allah has ninety-nine Names, one-hundred less one; and he who memorized them all by heart will enter Paradise." To count something means to know it by heart.
— Sahih Bukhari, Volume 9, Book 93: Oneness, Uniqueness of Allah (Tawheed), Hadith #489
Narrated Abu Huraira: Allah's Apostle said, "Allah has ninety-nine Names, one-hundred less one; and he who memorized them all by heart will enter Paradise." To count something means to know it by heart.
This hadith is from the book of Oneness, Uniqueness of Allah (Tawheed) in Sahih Bukhari, compiled by Imam al-Bukhari. It is hadith number 489 in book 93 of volume 9.
This hadith is referenced in the following topics: Who enters Paradise.