Language:
كتاب الأيمان والنذور
83
Oaths and Vows
(15)
Chapter: If someone does something against his oath due to forgetfulness
(15)
بَابُ إِذَا حَنِثَ نَاسِيًا فِي الأَيْمَانِ
وَقَوْلِ اللَّهِ تَعَالَى: {وَلَيْسَ عَلَيْكُمْ جُنَاحٌ فِيمَا أَخْطَأْتُمْ بِهِ}.
وَقَالَ: {لاَ تُؤَاخِذْنِي بِمَا نَسِيتُ}.

Narrated Abu Huraira:

A man entered the mosque and started praying while Allah's Messenger (ﷺ) was sitting somewhere in the mosque. Then (after finishing the prayer) the man came to the Prophet (ﷺ) and greeted him. The Prophet (ﷺ) said to him, "Go back and pray, for you have not prayed. The man went back, and having prayed, he came and greeted the Prophet. The Prophet (ﷺ) after returning his greetings said, "Go back and pray, for you did not pray." On the third time the man said, "(O Allah's Messenger (ﷺ)!) teach me (how to pray)." The Prophet said, "When you get up for the prayer, perform the ablution properly and then face the Qibla and say Takbir (Allahu Akbar), and then recite of what you know of the Qur'an, and then bow, and remain in this state till you feel at rest in bowing, and then raise your head and stand straight; and then prostrate till you feel at rest in prostration, and then sit up till you feel at rest while sitting; and then prostrate again till you feel at rest in prostration; and then get up and stand straight, and do all this in all your prayers."

حَدَّثَنِي إِسْحَاقُ بْنُ مَنْصُورٍ، حَدَّثَنَا أَبُو أُسَامَةَ، حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ عُمَرَ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَجُلاً، دَخَلَ الْمَسْجِدَ يُصَلِّي وَرَسُولُ اللَّهِ صلى الله عليه وسلم فِي نَاحِيَةِ الْمَسْجِدِ، فَجَاءَ فَسَلَّمَ عَلَيْهِ فَقَالَ لَهُ ‏"‏ ارْجِعْ فَصَلِّ، فَإِنَّكَ لَمْ تُصَلِّ ‏"‏‏.‏ فَرَجَعَ فَصَلَّى، ثُمَّ سَلَّمَ فَقَالَ ‏"‏ وَعَلَيْكَ، ارْجِعْ فَصَلِّ، فَإِنَّكَ لَمْ تُصَلِّ ‏"‏‏.‏ قَالَ فِي الثَّالِثَةِ فَأَعْلِمْنِي‏.‏ قَالَ ‏"‏ إِذَا قُمْتَ إِلَى الصَّلاَةِ فَأَسْبِغِ الْوُضُوءَ، ثُمَّ اسْتَقْبِلِ الْقِبْلَةَ فَكَبِّرْ، وَاقْرَأْ بِمَا تَيَسَّرَ مَعَكَ مِنَ الْقُرْآنِ، ثُمَّ ارْكَعْ حَتَّى تَطْمَئِنَّ رَاكِعًا، ثُمَّ ارْفَعْ رَأْسَكَ حَتَّى تَعْتَدِلَ قَائِمًا، ثُمَّ اسْجُدْ حَتَّى تَطْمَئِنَّ، سَاجِدًا ثُمَّ ارْفَعْ حَتَّى تَسْتَوِيَ وَتَطْمَئِنَّ جَالِسًا، ثُمَّ اسْجُدْ حَتَّى تَطْمَئِنَّ سَاجِدًا، ثُمَّ ارْفَعْ حَتَّى تَسْتَوِيَ قَائِمًا، ثُمَّ افْعَلْ ذَلِكَ فِي صَلاَتِكَ كُلِّهَا ‏"‏‏.‏
Reference : Sahih al-Bukhari 6667
In-book reference : Book 83, Hadith 45
USC-MSA web (English) reference : Vol. 8, Book 78, Hadith 660
  (deprecated numbering scheme)