Sahih Bukhari Volume 8, Book 78, Hadith 6025

حَدَّثَنَا أَبُو الْوَلِيدِ، حَدَّثَنَا شُعْبَةُ، قَالَ أَخْبَرَنِي عَمْرٌو، عَنْ خَيْثَمَةَ، عَنْ عَدِيِّ بْنِ حَاتِمٍ، قَالَ ذَكَرَ النَّبِيُّ صلى الله عليه وسلم النَّارَ، فَتَعَوَّذَ مِنْهَا وَأَشَاحَ بِوَجْهِهِ، ثُمَّ ذَكَرَ النَّارَ، فَتَعَوَّذَ مِنْهَا، وَأَشَاحَ بِوَجْهِهِ ـ قَالَ شُعْبَةُ أَمَّا مَرَّتَيْنِ فَلاَ أَشُكُّ ـ ثُمَّ قَالَ ‏"‏ اتَّقُوا النَّارَ وَلَوْ بِشِقِّ تَمْرَةٍ، فَإِنْ لَمْ تَجِدْ فَبِكَلِمَةٍ طَيِّبَةٍ ‏"‏‏.

Narrated By 'Adi bin Hatim : The Prophet mentioned the (Hell) Fire and sought refuge (with Allah) from it, and turned his face to the other side. He mentioned the (Hell) Fire again and took refuge (with Allah) from it and turned his face to the other side. (Shu'ba, the sub-narrator, said, "I have no doubt that the Prophet repeated it twice.") The Prophet then said, "(O people!) Save yourselves from the (Hell) Fire even if with one half of a date fruit (given in charity), and if this is not available, then (save yourselves) by saying a good pleasant friendly word."