Why do Hindus consider charity as a responsibility towards society?
It is the responsibility of everyone to give charity. One should give charity as a duty towards society and expect nothing in return. It is very noble to feed a hungry person. However, imparting knowledge is even better. Feeding a person is momentary support. Imparting knowledge is permanent support.
In the Rig-Veda, it is said that of all charities imparting knowledge is best. It cannot be stolen or destroyed. With time it grows and continues giving happiness to many people.
Hindu religious texts suggest that charity in different forms must be given on festivals and special occasions. This charity must be given happily with love and devotion. One should leave the fruit thereof to God. He responds with great happiness and contentment.
In the Bhavishyapuran, 151/18, it is said that three kinds of charity are particularly meritorious - the giving of a cow, the giving of land and the giving of knowledge. It is believed that the benefits continue for seven generations.
In the Manusmriti, 4/229-234, some interesting benefits of giving charity are explained. It is said that whoever feeds a hungry person finds great satisfaction. One who gives sesame seeds in charity is blessed with cherished progeny. One who gives a lamp or some form of light in charity is blessed with good eyesight. One who donates land receives land in return. Whoever donates gold is blessed with long life. Those who donate silver are blessed with beauty and charm. Of all charities, the best is teaching of the Vedas.