The Messenger of Allah ﷺ entered the mosque, and a man came in and prayed. He then greeted the Prophet ﷺ with the salam, and the Prophet returned the greeting and said, "Go back and pray, for you have not prayed."The man went back and prayed as he had prayed before, then came and greeted the Prophet ﷺ again. The Prophet said, "Go back and pray, for you have not prayed." This happened three times.The man said, "By the One who sent you with the truth, I cannot do it any better than this. Teach me."The Prophet said, "When you stand for prayer, say the takbir, then recite whatever you can of the Quran. Then bow until you are at ease in bowing, then rise until you are standing upright, then prostrate until you are at ease in prostration, then rise until you are at ease sitting. Do that throughout your entire prayer."
أن رسول الله ﷺ دخل المسجد، فدخل رجل فصلى، فسلم على النبي ﷺ فرد وقال: ارجع فصل فإنك لم تصل، فرجع يصلي كما صلى، ثم جاء فسلم على النبي ﷺ فقال: ارجع فصل فإنك لم تصل- ثلاثا. فقال: والذي بعثك بالحق ما أحسن غيره، فعلمني، فقال: إذا قمت إلى الصلاة فكبر، ثم اقرأ ما تيسر معك من القرآن، ثم اركع حتى تطمئن راكعا، ثم ارفع حتى تعدل قائما، ثم اسجد حتى تطمئن ساجدا، ثم ارفع حتى تطمئن جالسا، وافعل ذلك في صلاتك كلها.
Bukhari related it in the Book of Adhan (757), and Muslim in the Book of Prayer (397), both through the route of Yahya bin Saeed Qattan, from Ubaydullah, who said, "Saeed bin Abu Saeed narrated to me, from his father, from Abu Hurairah," and then mentioned the hadith.This is how Yahya related it, saying in it, "from his father." Others related it from Ubaydullah without saying in it "from his father," and both versions are sahih, for Saeed was not one who practiced tadlis, and his hearing from Abu Hurairah is established, so the isnad is sound through both routes. This is why the two Shaykhs (Bukhari and Muslim) related it through both versions.