Jabir reported that the Messenger of Allah, may Allah bless him and grant him peace, said, “Every act of kindness is sadaqa. Part of kindness is that you offer your brother a cheerful face and you pour some of your bucket into his water vessel.”
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا ابْنُ الْمُنْكَدِرِ، عَنْ أَبِيهِ، عَنْ جَابِرٍ قَالَ‏:‏ قَالَ رَسُولُ اللهِ صلى الله عليه وسلم‏:‏ كُلُّ مَعْرُوفٍ صَدَقَةٌ، إِنَّ مِنَ الْمَعْرُوفِ أَنْ تَلْقَى أَخَاكَ بِوَجْهٍ طَلْقٍ، وَأَنْ تُفْرِغَ مِنْ دَلْوِكَ فِي إِنَاءِ أَخِيكَ‏.‏
Arabic/English book reference : Book 14, Hadith 304