Sayyiduna Samurah (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "After the Qur'an, the most excellent speech is four phrases (and they are, in fact, part of the Qur'an); whichever of them you begin with, it will do you no harm. These phrases are: 'Subhanallah, wal-hamdu lillah, wa la ilaha illallah, wallahu akbar' (Glory be to Allah, all praise is for Allah, there is no deity except Allah, and Allah is the Greatest)."
(Allamah Haythami says:) I say:
This narration is in the Sahih, but without these words: "after the Qur'an" and "they are, in fact, part of the Qur'an."
Ahmad recorded it, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 16840
Hadith Gradingمحدثین:إسنادہ صحیح
Hadith Takhrij«اخرجه احمد فى المسند (20/5) ، أخرجه مسند أحمد برقم: 19732»