According to tradition (hadith), there are 99 names of God in Islam, known as the ʾasmāʾu 'llāhi 'l-ḥusnā (Arabic: أسماء الله الحسنى) " of God" (also أسماء الحسنى ʾasmāʾu 'l-ḥusnā "Beautiful Names").
According to 9th-century collections of hadith, the tradition of there being "99 names" is sahih (reliable), while the tradition of the actual list of 99 names as given by some collectors, in at least three different variants, is stated to be gharib (scarce, unreliable). Most names in these lists are divine epithets taken from the text of the Quran, with a minority based in oral tradition or Sunnah. The lists of names vary because there are more than 99 such epithets to choose from.
Different sources give different lists of the 99 names.
In the hadith, Muhammad is said to have invoked God by a number of names. The origin of the number 99 specifically is commonly attributed to a hadith considered weak, although there are less-commonly cited hadith that are considered authentic and also support the same point. According to Sahih Muslim, 35:6475:
Abu Hurairah reported Allah's Messenger [Muhammad] (may peace be upon him) as saying: "There are ninety-nine names of Allah; he who commits them to memory would get into Paradise. Verily, Allah is Odd and He loves odd numbers. And in the narration of Ibn 'Umar [the words are]: 'He who enumerated them'."