Sahih Muslim
Book 1: The Book of Faith
كتاب الإيمان
439 hadith in this book
It is narrated on the authority of Abu Huraira that the Messenger of Allah (ﷺ) observed: Be prompt in doing good deeds (before you are overtaken) by turbulence which would be like a part of the dark night. During (that stormy period) a man would be a Muslim in the morning and an unbeliever in the evening or he would be a believer in the evening and an unbeliever in the morning, and would sell his faith for worldly goods.
حَدَّثَنِي يَحْيَى بْنُ أَيُّوبَ، وَقُتَيْبَةُ، وَابْنُ، حُجْرٍ جَمِيعًا عَنْ إِسْمَاعِيلَ بْنِ جَعْفَرٍ، - قَالَ ابْنُ أَيُّوبَ حَدَّثَنَا إِسْمَاعِيلُ، - قَالَ أَخْبَرَنِي الْعَلاَءُ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " بَادِرُوا بِالأَعْمَالِ فِتَنًا كَقِطَعِ اللَّيْلِ الْمُظْلِمِ يُصْبِحُ الرَّجُلُ مُؤْمِنًا وَيُمْسِي كَافِرًا أَوْ يُمْسِي مُؤْمِنًا وَيُصْبِحُ كَافِرًا يَبِيعُ دِينَهُ بِعَرَضٍ مِنَ الدُّنْيَا " .
Hadith text, translations and grading are courtesy of Sunnah.com.