(a) It is narrated from Sayyiduna Rifa'ah bin Rafi' (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) — he related the story of the man's prayer. In it, what the Prophet (peace and blessings be upon him) taught that man is: "When you stand for prayer, perform ablution as Allah has commanded you. Then recite the tashahhud, then stand and say the takbir. If you know some of the Qur'an, recite it; otherwise, praise Allah, declare His greatness and say 'La ilaha illallah' (There is no god worthy of worship except Allah)."
(b) At the end of it, it says: "If you leave out anything from it, you will have reduced your prayer by that much."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3975
Abdullah bin Abi Awfa (may Allah be pleased with him) narrates that a man came to the Messenger of Allah (peace and blessings be upon him) and said: I cannot recite the Qur'an well; teach me something that will suffice me in place of the Qur'an. He (peace and blessings be upon him) said: "Say: 'Al-hamdu lillah, wa subhan Allah, wa la ilaha illallah, wallahu akbar, wa la hawla wa la quwwata illa billah' (All praise is for Allah; glory be to Allah; there is no god but Allah; Allah is the Greatest; and there is no might nor power except with Allah)." When he had counted them off on his fingers, he said: O Messenger of Allah, these are for my Lord; what should I say for myself? He (peace and blessings be upon him) said: "Say: 'Allahumma ighfir li, warhamni, wahdini, warzuqni, wa 'afini' (O Allah, forgive me, have mercy on me, guide me, provide for me and grant me well-being)." The narrator says: He memorised these words as well, and then went away. The Messenger of Allah (peace and blessings be upon him) said: "This man has filled both his hands with good."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3977
Sayyiduna Abdullah bin Abi Awfa (may Allah be pleased with him) narrates that a man came to the Prophet (peace and blessings be upon him) and said: I am not able to memorise anything of the Qur'an; teach me something that will suffice me in place of the Qur'an. He (peace and blessings be upon him) said: "'Subhan Allah, wal-hamdu lillah, wa la ilaha illallah, wallahu akbar, wa la hawla wa la quwwata illa billah' (Allah is free of all imperfection; all praise is for Allah; there is no god worthy of worship except Allah; Allah is the Greatest; and there is no strength to avoid sin nor power to do good except through the enabling of Allah)." The narrator says: He stood up and left, or did something of that sort, and said: These are for Allah; what is there for me? He (peace and blessings be upon him) said: "Say: 'Allahumma ighfir li, warhamni, wa 'afini, warzuqni' (O Allah, forgive me, have mercy on me, grant me well-being and provide for me)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3978
Ibn Abi Awfa (may Allah be pleased with him) says that a man came to the Prophet (peace and blessings be upon him) and said: O Messenger of Allah, I cannot recite the Qur'an well; teach me something that will suffice me in place of it. He (peace and blessings be upon him) said: "Say: 'Subhan Allah, wal-hamdu lillah, wa la ilaha illallah, wallahu akbar, wa la hawla wa la quwwata illa billah' (Glory be to Allah; all praise is for Allah; there is no god but Allah; Allah is the Greatest; and there is no might nor power except with Allah)." He went away, then came back and said: These are for my Lord; what is there for me? He (peace and blessings be upon him) said: "Say: 'Allahumma ighfir li, warhamni, wahdini, warzuqni, wa 'afini, wa'fu 'anni' (O Allah, forgive me, have mercy on me, grant me guidance and provision, grant me well-being and pardon me)." When the man had gone, the Messenger of Allah (peace and blessings be upon him) said: "This man has filled both his hands with good."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3979