It is narrated from Sayyiduna Abu Dharr (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "O Abu Dharr, never belittle any good deed, even if it is meeting your brother with a cheerful face, or pouring from your bucket into the vessel of one who asks for water. And when you cook a pot, add more broth to it and ladle some out of it for your neighbours."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7824