It is narrated from Sayyiduna Rifa’ah bin Rafi’ (may Allah be pleased with him) that while the Messenger of Allah (peace and blessings of Allah be upon him) was sitting in the mosque one day, Rifa’ah says, and we were also sitting in his service, a man came who seemed to be a Bedouin. He prayed, and he prayed a brief prayer. After finishing the prayer, he greeted the Prophet (peace and blessings of Allah be upon him), so the Prophet (peace and blessings of Allah be upon him) said:“Peace be upon you too, go back and pray, for you have not prayed.”The man went back, prayed, then came to the Prophet (peace and blessings of Allah be upon him) and greeted him. The Prophet (peace and blessings of Allah be upon him) replied to his greeting and said:“Go back and perform the prayer, for you have not performed the prayer.”The man prayed in this (brief and light) manner two or three times. Each time he would come to the Prophet (peace and blessings of Allah be upon him), greet him, and the Prophet (peace and blessings of Allah be upon him) would say:“Peace be upon you too, go back and pray, for you have not prayed.”The Companions became afraid and found it very hard that the prayer of a person who prayed briefly would not be valid at all. Eventually, the man said: O Messenger of Allah, show me (how to pray) or teach me (how to pray), for indeed I am a human being, I make mistakes and I also do things correctly. The Prophet (peace and blessings of Allah be upon him) said:“Certainly (I will teach you). When you stand for prayer, perform ablution according to Allah’s command, then testify to the two testimonies, then say the iqamah «‏‏‏‏اللهُ أَكْبَرُ» ‏‏‏‏, then if you know any part of the Qur’an, recite it, otherwise praise and glorify Allah «‏‏‏‏الحَمْدُ لِلَٰه» ‏‏‏‏, declare His greatness «‏‏‏‏اللهُ أَكْبَرُ» ‏‏‏‏, and His oneness «‏‏‏‏لَا إِلٰهَ إِلَّا الله» ‏‏‏‏. Then bow (ruku’) and perform ruku’ with calmness, then stand up straight. Then prostrate (sajdah) and perform it fully, then sit with complete calmness, then stand up for the next rak’ah. When you perform the prayer in this manner, your prayer will be complete, and if you leave out any of these things, your prayer will be incomplete.”He says that this was easier for the Companions than the Prophet’s (peace and blessings of Allah be upon him) first statement, that whoever leaves something out, his prayer will be deficient, but the complete prayer will not be invalidated.