Narrated Abu Hurairah:
that the Messenger of Allah (ﷺ) said: "Al-Hamdulillah is Umm Al-Qur'an and Umm Al-Kitab and the seven oft-repeated." (ID)
English reference (ID): Vol. 5, Book 44, Hadith 3124 (ID)
Arabic reference (ID): Book 47, Hadith 3415 (ID)