From Sahih Bukhari (Hadith 6560):
Narrated Abu Sa`id Al-Khudri:Allah's Messenger (ﷺ) said, "When the people of Paradise have entered Paradise, and the people of the Fire have entered the Fire, Allah will say. 'Take out (of the Fire) whoever has got faith equal to a mustard seed in his heart.' They will come out, and by that time they would have burnt and became like coal, and then they will be thrown into the river of Al-Hayyat (life) and they will spring up just as a seed grows on the bank of a rainwater stream." The Prophet (ﷺ) said, "Don't you see that the germinating seed comes out yellow and twisted?
Reference: Bukhari 6560