Sayyiduna Anas bin Malik (may Allah be pleased with him) states: One day the Prophet (peace and blessings be upon him) said to those sitting with him: "Prepare your protection!" The people said: "O Messenger of Allah, may our fathers and mothers be sacrificed for you, has an enemy come?" The Prophet (peace and blessings be upon him) said: "Prepare your protection from Hell! Recite 'Subhanallah' (Glory be to Allah), 'Al-hamdu lillah' (All praise is for Allah), 'La ilaha illallah' (There is no deity except Allah), 'Allahu akbar' (Allah is the Greatest) and 'La hawla wa la quwwata illa billah' (There is no power and no strength except with Allah), for these are things that go ahead, these are things that save, these are mu'aqqibat, and these are the enduring good deeds (al-baqiyat al-salihat)."
Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains a narrator, Kathir bin Sulaym, who is da'if (weak); Ibn Hibban mentioned him in both al-Du'afa' and al-Thiqat.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 16847