Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated from the Messenger of Allah (peace and blessings be upon him), he (peace be upon him) said: "It is obligatory for every Muslim to give charity every day." They asked: O Messenger of Allah! Who has the ability to do this? He (peace be upon him) said: "Removing something harmful from the road is charity, guiding a Muslim on the way is charity, visiting a sick Muslim is charity, participating in a funeral is charity, replying to the greeting of a Muslim is charity." Muhammad bin Fudayl bin Ghazwan narrated a similar narration with this chain, the narrator stated: They said: Who has the ability to do this? He (peace be upon him) said: "Removing something harmful from the road is charity, visiting a sick person is charity, participating in a funeral is charity, enjoining good and forbidding evil is charity, replying to the greeting of a Muslim is charity."
Hadith Referenceمسند اسحاق بن راهويه / كتاب البر و الصلة / 767
Hadith Takhrij«بخاري ، كتاب الجهاد ، باب من اخذ بالركا ب ونحوه ، رقم : 2989 . مسلم كتاب الزكاة ، باب بيان ان اسم الصدقة الخ ، رقم : 1009 . مسند احمد : 328/2 .»