The Prophet Muhammad (peace be upon him) said: "Giving in charity is prescribed for each descendant of Adam every day the sun rises." People then asked him: "From what do we give charity if we do not possess property?" He replied: "The doors of goodness are many - (saying) 'glory to God,' 'praise be to God,' 'there is no deity but God,' enjoining good, forbidding evil, removing harm from the road, listening to the deaf (until you understand them), leading the blind, guiding one to the object of his need, hurrying with the strength of one's legs to one in sorrow who is asking for help, and supporting the weak with the strength of one's arms - all of these are (forms of) charity prescribed for you."

Fiqh-us-Sunnah, Volume 3, Number 98