Language:
كتاب الأدب
78
Good Manners and Form (Al-Adab)
(74)
Chapter: Whoever does not consider as Kafir the person who says that...
(74)
باب مَنْ لَمْ يَرَ إِكْفَارَ مَنْ قَالَ ذَلِكَ مُتَأَوِّلاً أَوْ جَاهِلاً
وَقَالَ عُمَرُ لِحَاطِبٍ إِنَّهُ مُنَافِقٌ، فَقَالَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «وَمَا يُدْرِيكَ لَعَلَّ اللَّهَ قَدِ اطَّلَعَ إِلَى أَهْلِ بَدْرٍ فَقَالَ قَدْ غَفَرْتُ لَكُمْ».
Sahih al-Bukhari 6106

Narrated Jabir bin `Abdullah:

Mu`adh bin Jabal used to pray with the Prophet (ﷺ) and then go to lead his people in prayer. Once he led the people in prayer and recited Surat-al-Baqara. A man left (the row of the praying people) and offered (light) prayer (separately) and went away. When Mu`adh came to know about it, he said. "He (that man) is a hypocrite." Later that man heard what Mu`adh said about him, so he came to the Prophet and said, "O Allah's Messenger (ﷺ)! We are people who work with our own hands and irrigate (our farms) with our camels. Last night Mu`adh led us in the (night) prayer and he recited Sura-al-Baqara, so I offered my prayer separately, and because of that, he accused me of being a hypocrite." The Prophet called Mu`adh and said thrice, "O Mu`adh! You are putting the people to trials? Recite 'Washshamsi wad-uhaha' (91) or'Sabbih isma Rabbi ka-l-A'la' (87) or the like."

حَدَّثَنَا مُحَمَّدُ بْنُ عَبَادَةَ، أَخْبَرَنَا يَزِيدُ، أَخْبَرَنَا سَلِيمٌ، حَدَّثَنَا عَمْرُو بْنُ دِينَارٍ، حَدَّثَنَا جَابِرُ بْنُ عَبْدِ اللَّهِ، أَنَّ مُعَاذَ بْنَ جَبَلٍ ـ رضى الله عنه ـ كَانَ يُصَلِّي مَعَ النَّبِيِّ صلى الله عليه وسلم ثُمَّ يَأْتِي قَوْمَهُ فَيُصَلِّي بِهِمُ الصَّلاَةَ، فَقَرَأَ بِهِمُ الْبَقَرَةَ ـ قَالَ ـ فَتَجَوَّزَ رَجُلٌ فَصَلَّى صَلاَةً خَفِيفَةً، فَبَلَغَ ذَلِكَ مُعَاذًا فَقَالَ إِنَّهُ مُنَافِقٌ‏.‏ فَبَلَغَ ذَلِكَ الرَّجُلَ، فَأَتَى النَّبِيَّ صلى الله عليه وسلم فَقَالَ يَا رَسُولَ اللَّهِ إِنَّا قَوْمٌ نَعْمَلُ بِأَيْدِينَا، وَنَسْقِي بِنَوَاضِحِنَا، وَإِنَّ مُعَاذًا صَلَّى بِنَا الْبَارِحَةَ، فَقَرَأَ الْبَقَرَةَ فَتَجَوَّزْتُ، فَزَعَمَ أَنِّي مُنَافِقٌ‏.‏ فَقَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ يَا مُعَاذُ أَفَتَّانٌ أَنْتَ ـ ثَلاَثًا ـ اقْرَأْ ‏{‏وَالشَّمْسِ وَضُحَاهَا‏}‏ وَ‏{‏سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى‏}‏ وَنَحْوَهَا ‏"‏‏.‏
Reference : Sahih al-Bukhari 6106
In-book reference : Book 78, Hadith 133
USC-MSA web (English) reference : Vol. 8, Book 73, Hadith 127
  (deprecated numbering scheme)