Surah al-Ikhlas is four ayat long, and according to multiple Sahih hadith reported by both Bukhari and Muslim, the Prophet declared it equivalent to a third of the Quran. Classical commentary explains the equivalence in terms of subject matter: the Quran has three principal themes — tawhid (divine unity), prophethood, and eschatology — and al-Ikhlas concentrates the first of these into its purest form. To recite it three times is, by this accounting, to traverse the doctrinal weight of the entire Quran. It has functioned for fourteen centuries as the most-recited surah in daily Muslim devotion after al-Fatihah.