It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that one day the Prophet (peace and blessings be upon him) said to those sitting with him: "Take up your shields." They said: "O Messenger of Allah (peace and blessings be upon him)! May our fathers and mothers be ransomed for you, has an enemy appeared?" He (peace and blessings be upon him) said: "Take up your shields against the Fire of Hell. Say: 'Subhan Allah, wal-hamdu lillah, wa la ilaha illallah, wallahu akbar, wa la hawla wa la quwwata illa billah' (Glory be to Allah, all praise is for Allah, there is no god worthy of worship except Allah, Allah is the Greatest, and there is no power to avoid sin and no strength to do good except through Allah). For these words will be (on the Day of Resurrection) those that go in front of you, those that guard you from the sides, and guardians that come from behind, and they are 'the lasting good deeds'."
Hadith Referenceالمعجم الأوسط / باب الباء / 3179
Hadith Gradingمحدثین:إسناده ضعيف لضعف كثير بن سليم
Hadith Takhrij«قال الهيثمي: وفيه كثير بن سليم وهو ضعيف وذكره ابن حبان في الثقات والضعفاء «مجمع الزوائد ومنبع الفوائد، ج 10، ص 89»»