‘Abdallah b. ‘Umar told that the Prophet (ﷺ) used to say, “Everything has a polish, and the polish for hearts is rememberance of Allah. Nothing is more calculated to resuce from Allah’s punishment than remembrance of Allah.” He was asked whether this did not apply also to jihad in Allah’s path, and said, “Not even if one should ply his sword till it is broken.” Baihaqi transmitted it in [Kitab] ad-Da'awat al-kabir.