In Islam, every Muslim is obliged to give to charity in whatever form to boost his piety and spread wealth and goodwill among the whole community. It's no surprise then that the Arabic word tasadaqa (to give charity) is derived from the word "sadaqa" which means tell the truth or be sincere.
Allah (SWT) says in the Noble Qur'an: "By no means shall you attain to righteousness until you spend (benevolently) out of what you love; and whatever thing you spend, Allah surely knows it." (3:92)
Therefore voluntary charity, or sadaqa, which is different than the zakah - the compulsory alms that are collected each year - should be part of every Muslim's daily life. Prophet Muhammad (S) said that every good deed is charity - even a smile in the face of others is charity.
Prophet Muhammad (S) said: "There is no person who does not have the obligation of doing charity every day that the sun rises." Whereupon he was asked: "O Messenger of Allah (SWT), from where would we get something to give in charity (so often)?" Prophet Muhammad (S) replied: "Indeed the gates to goodness are many: glorifying Allah (SWT), praising Him, magnifying Him, saying 'There is no god but Allah', enjoining the good and forbidding the evil, removing (any source of harm from the road, listening to the aggrieved, guiding the blind, showing the seeker his need, striving as far as your two legs could carry you and with deep concern to give succour to him who asks, carrying with the strength of your arms (the burdens of) the weak. All these are acts of charity which are an obligation on you." And Prophet Muhammad (S) added: "And your smiling in the face of your brother is charity, your removing of stones and thorns from people's paths is charity, and your guiding a man gone astray in the world is charity for you."
Charity, as it is traditionally understood, consists of money or various objects given by the rich to help the poor or by the strong to help the weak. Charity in its tangible, narrow sense divides people into the receivers on the one hand and the givers on the other. This division inspires among the receivers feelings of weakness and even of error, and among those who give feelings of pride and conceit. But the saying of Prophet Muhammad (S), however, takes charity out of this narrow, physical meaning and on to a spiritual plane that opens up a vast and limitless world by emphasizing that every good is charity. And on every person is the obligation of charity. This is a unique concept of charity.
Prophet Muhammad (S) makes us realize the single spiritual essence which lies behind every act of goodness. But Prophet Muhammad (S) does not want us merely to know. Knowledge is not an end in itself. Prophet Muhammad (S) wants to make us return to goodness, goodness which is the very word of Allah (SWT). Prophet Muhammad (S) wants that each of us should move and stir ourselves from within into goodness so that giving would become a habit of life, and that this habit would pass from person to person. The complete Islamic concept of charity which includes all good actions however small they may be, allows every person whether rich or poor, to become givers and receivers on an equal basis. This point to another basic principle of Islamic thought and behaviors that the standard on which life is judged is not the materialistic alone but one based on faith, feeling and sensitivity which form the center of human relations. And from it comes the ties of faith, affection and love to bind hearts.
Allah (SWT) says in the Noble Qur'an: "And united their (believers) hearts; had you spent all that is in the earth, you could not have united their hearts, but Allah united them; surely He is Mighty, Wise." (8:63)
Prophet Muhammad (S) has said: "No one of you believes until he loves for his brother what he loves for himself."
This is the essence of charity. So begin by meeting your brother and sister with a smile. This would open up locked souls, penetrate to the depths of the heart and exert a magnetic bond on society. Read the hadith again and see how it reaches into the depths of the soul, the essence of existence and creates hearts that are tender, pure, radiant and beautiful.
And Abdullaah Ibn Haarith said: "I never came across a person who smiled as much as Prophet Muhammad (S). Prophet Muhammad (S) regarded smiling with a brother as an act of charity." (Tirmidhi)
Indeed every act of giving is charity, even a smile in the face of your fellow.
Prophet Muhammad (S) was asked if acts of charity even to the animals were rewarded by Allah (SWT). He replied: 'yes, there is a reward for acts of charity to every beast alive.' (Bukhari, Muslim)