Abu Bakr bin Abdur Rahman bin Harith bin Hisham narrates that indeed Ammar bin Yasir (may Allah be pleased with them both) entered the mosque and performed two light rak‘ahs. A man said to him: O Abu Yaqzan! Surely I have memorized them. He replied: Did you see me omit anything from their prescribed limits? Rather, I shortened them; I hastened in them due to forgetfulness. I heard the Messenger of Allah (peace and blessings be upon him) say: "Indeed, a man certainly performs prayer, and perhaps nothing of his prayer is recorded for him except a tenth, a ninth, an eighth, a seventh, or a fifth of it."