Sahih Muslim 1016
Sahih Muslim · Book 12: The Book of Zakat · Encouragement to give charity even if it is with half a date or a kind word. And charity is a shield against the fire.
Adi b. Hatim reported that the Messenger of Allah (ﷺ) made a mention of the Fire and sought refuge (with Allah against it). He turned aside his face three times and then said:
وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى ، وَابْنُ، بَشَّارٍ قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ ، حَدَّثَنَا شُعْبَةُ ، عَنْ عَمْرِو بْنِ مُرَّةَ ، عَنْ خَيْثَمَةَ ، عَنْ عَدِيِّ بْنِ حَاتِمٍ ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم أَنَّهُ ذَكَرَ النَّارَ فَتَعَوَّذَ مِنْهَا وَأَشَاحَ بِوَجْهِهِ ثَلاَثَ مِرَارٍ ثُمَّ قَالَ " اتَّقُوا النَّارَ وَلَوْ بِشِقِّ تَمْرَةٍ فَإِنْ لَمْ تَجِدُوا فَبِكَلِمَةٍ طَيِّبَةٍ " .
Protect yourselves against Fire even if with half a date. But if you fail to find it (then protect yourselves against Fire) with the help of a pleasant word).