"When your brother becomes poor and he slips down among you, you must come to his aid, [even to] a convert and a [non-Jewish] settler, so that he can live with you."
VaYikra (Leviticus) 25:35

"When any of your brothers is poor in any of your cities, in the land which HaShem your God is giving you, do not harden your heart or shut your hand from your poor brother. You shall open your hand, and you shall lend him whatever he needs, whatever he is lacking."
Devarim (Deuteronomy) 14:7-8

The Torah instructs us to give tzedaka (charity) to the poor. Charity is one of the greatest mitzvos (commandments), as we see in Mishlei (Proverbs) 21:3, "Doing tzedaka and justice is preferable to HaShem than a sacrifice". It is through the mitzvah of tzedaka that the Jews shall be redeemed, as it says, "Zion will be redeemed through justice, and those who return to her through tzedaka" (Yeshaya (Isaiah) 1:27).

Tzedaka is a very important and significant Jewish characteristic, as HaShem said, "For I have loved him because he [Avrohom] commands his children and his household after him that they keep the way of HaShem, doing tzedaka and justice... (B'reishis (Genesis) 18:19). Generosity in giving tzedaka demonstrates a basic principle in Judaism, that our money and possessions are not truly ours, but are merely given over to us by HaShem to use as He commands us to.

Every person is required to give tzedaka according to his ability. Even a poor person who is himself supported by tzedaka, must give tzedaka. A person who can only give a little should not hesitate to give, because a little from him is like a great deal from a wealthier person. However, a person who is unable provide for his own needs is not required to give since his own needs take precedence.

A person should give ten percent of his earnings to tzedaka. It is an even greater fulfillment of the mitzvah to give twenty percent. However, one should not exceed that amount lest one impoverish himself and thus have to take tzedaka himself.

If one gives tzedaka to a poor person with a sour and unpleasant face, then he loses any merit from it, even if he gives "a thousand golden coins." Tzedaka must be given in a pleasant and compassionate manner. It is forbidden to turn a poor person away completely empty-handed, as it says, "Let not the oppressed turn back in shame…" (Tehillim (Psalms) 74:21) but you should give something, even if it is only a small amount. If you have nothing to give you should appease the poor person with words. It is forbidden to scold or yell at a poor person.

It is proper to try to give charity in a secretive way, that the recipient should not know who he is receiving tzedaka from. It is even better if the giver does not know who the recipient is. One should certainly not try to glorify himself through giving charity. However, it is permitted to donate something to charity and have your name inscribed as a memorial.

It is particularly important to support poor Torah scholars in a respectable manner. If he refuses to accept tzedaka, then one should help him in less direct ways, such as selling him things for cheaper or helping him make a living.

A person should do his best to avoid having to take tzedaka. This even means if he has to lower his lifestyle or take a lowly job. Someone who needs to take tzedaka but instead lives at a greatly reduced level is blessed. However, if this involves risk to his life, such as if he is old or sick, then this is forbidden and he is required to accept tzedaka.