the Messenger of Allah (saas) said: "The Greatest Name of Allah is in these two Verses: And your Ilah (God) is One Ilah (God - Allah), La Ilaha Illa Huwa (none has the right to be worshipped but He), the Most Gracious, the Most Merciful.' And at the beginning of Surah Al 'Imran."
Sunan Ibn Majah Book 34, Hadith 29
← Previous Hadith Messenger of Allah (saas) said: "No one among you should say: "O Allah, forgive me if You will.' Let him be definite in his asking, and no one can compel Allah."

Sunan Ibn Majah Book 34, Hadith 28 Next Hadith → The Greatest Name of Allah, if He is called by which He will respond, is in three Surah: Al-Baqarah, Al 'Imran and Ta-Ha. (Hasan)Another chain for something similar from Al-Qasim, from Abu Umamah, from the Prophet (saas).

Sunan Ibn Majah Book 34, Hadith 30