It is narrated from Hazrat Buraidah (may Allah be pleased with him) that I heard the Noble Prophet (peace and blessings be upon him) say: Every human being has three hundred and sixty joints, and it is obligatory to give charity on behalf of each joint. The people asked, "O Messenger of Allah! Who has the strength to do this?" The Noble Prophet (peace and blessings be upon him) said: The way to do this is that if you see spit in the mosque, cover it with earth; remove something harmful from the path; and if you cannot do all this, then two rak'ahs at the time of Duha will suffice on your behalf.