Abu Huraira reported Prophet Muhammad SAW as saying: Verily, there are ninety-nine names for Allah, i.e. hundred excepting one. He who enumerates them would get into Paradise. And Hammam has made this addition on the authority of Abu Huraira who reported it from Prophet Muhammad SAW that he said: “He is Odd (one) and loves odd number.”
(Sahih Muslim – Book 35 Hadith 6476).

Narrated Abu Huraira: Prophet Muhammad SAW said, “Allah has ninety-nine names, i.e. one-hundred minus one, and whoever knows them will go to Paradise.”
(Sahih Al-Bukhari – Book 50 Hadith 894)

Abu Huraira reported: The Messenger of Allah, peace and blessings be upon him, said, “Allah has ninety-nine names, and whoever preserves them will enter Paradise.”

Source: Sahih Muslim 2677
Grade: Sahih (authentic) according to Imam Muslim