The Messenger of Allah ﷺ said, "Allah has ninety-nine names, one hundred less one. Whoever preserves them will enter Paradise. He is One, and He loves what is odd in number."
أن رسول الله ﷺ قال: الله تسعة وتسعون اسما مائة إلا واحدا، لا يحفظها أحد إلا دخل الجنة، وهو وتر يحب الوتر.
Bukhari related it in the Book of Supplications (6410), and Muslim in the Book of Remembrance and Supplication (2677:5), both through the route of Sufyan bin Uyayna, from Abu Zinad, from Araj, from Abu Hurairah, who narrated it.The mention of the names is found in some of the routes, but it is not sound, and the discussion of this is set out at length in the Book of Faith.