Allah's Messenger (ﷺ) 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 al-Bukhari Book 97, Hadith 21
← Previous Hadith The Prophet (ﷺ) frequently used to swear, "No, by the One Who turns the hearts."

Sahih al-Bukhari Book 97, Hadith 20 Next Hadith → The Prophet (ﷺ) said, "When anyone of you goes to bed, he should dust it off thrice with the edge of his garment, and say: Bismika Rabbi Wada`tu janbi, wa bika arfa'hu. In amsakta nafsi faghfir laha, wa in arsaltaha fahfazha bima tahfaz bihi 'ibadaka-s-salihin."

Sahih al-Bukhari Book 97, Hadith 22