It is reported that before his death, Abū Mūsā Al-Ash’arī – Allah be please with him – used to exert himself intensely in worship. It was said to him, “If only you would slow down and go easy on yourself.” He replied, “When steeds are let loose and come close to the end of their course they finish by giving it all they have, and what remains of my life is less than that.”
Al-Dhahabī , Siyar A’lām Al-Nubalā` in his biography of Abū Mūsā Al-Ash’arī.