كتاب الإيمان
1
The Book of Faith
(82)
Chapter: Intercession and bringing those who believed in tawhid out of the Fire
(82)
باب إِثْبَاتِ الشَّفَاعَةِ وَإِخْرَاجِ الْمُوَحِّدِينَ مِنَ النَّارِ ‏‏

Abu Sa'id al-Khudri reported:

Verily the Messenger of Allah (ﷺ) said: Allah will admit into Paradise those deserving of Paradise, and He will admit whom He wishes out of His Mercy, and admit those condemned to Hell into the Fire (of Hell). He would then say: See, he whom you find having as much faith in his heart as a grain of mustard, bring him out. They will then be brought out burned and turned to charcoal, and would be cast into the river of life, and they would sprout aj does a seed in the silt carried away by flood. Have you not seen that it comes out yellow (fresh) and intertwined?
وَحَدَّثَنِي هَارُونُ بْنُ سَعِيدٍ الأَيْلِيُّ، حَدَّثَنَا ابْنُ وَهْبٍ، قَالَ أَخْبَرَنِي مَالِكُ بْنُ أَنَسٍ، عَنْ عَمْرِو بْنِ يَحْيَى بْنِ عُمَارَةَ، قَالَ حَدَّثَنِي أَبِي، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏ "‏ يُدْخِلُ اللَّهُ أَهْلَ الْجَنَّةِ الْجَنَّةَ يُدْخِلُ مَنْ يَشَاءُ بِرَحْمَتَهِ وَيُدْخِلُ أَهْلَ النَّارِ النَّارَ ثُمَّ يَقُولُ انْظُرُوا مَنْ وَجَدْتُمْ فِي قَلْبِهِ مِثْقَالَ حَبَّةٍ مِنْ خَرْدَلٍ مِنْ إِيمَانٍ فَأَخْرِجُوهُ ‏.‏ فَيُخْرَجُونَ مِنْهَا حُمَمًا قَدِ امْتَحَشُوا ‏.‏ فَيُلْقَوْنَ فِي نَهْرِ الْحَيَاةِ أَوِ الْحَيَا فَيَنْبُتُونَ فِيهِ كَمَا تَنْبُتُ الْحِبَّةُ إِلَى جَانِبِ السَّيْلِ أَلَمْ تَرَوْهَا كَيْفَ تَخْرُجُ صَفْرَاءَ مُلْتَوِيَةً ‏"‏ ‏.‏
Reference : Sahih Muslim 184 a
In-book reference : Book 1, Hadith 364
USC-MSA web (English) reference : Book 1, Hadith 355
  (deprecated numbering scheme)