Bismillah.
Kitaab-uz-Zakah [Book of the Obligatory Charity Tax] starts today..
Volume 2, Book 24, Number 484:
Narrated Jarir bin 'Abdullah ,
I gave the pledge of allegiance to the Prophet for offering prayer perfectly giving Zakat and giving good advice to every Muslim.
What is Zakah?
Zakah is one of the five pillars of Islam and is a duty performed on a regular basis. Zakah is not an option it is a compulsory act for all Muslims. It is a contribution paid once a year on savings of two and a half percent. This giving is to “cleanse” your money and possessions from excessive desire for them or greed. The idea is, that by giving this money you learn not to place too much importance on material wealth (cash and possessions).
Zakah is a compulsory payment and is neither charity nor a tax. It is expected from every Muslim individual. It is paid on the net balance after a Muslim has spent on basic necessities, family expenses, due credits, donations and taxes.
Zakah provides us with the opportunity of sharing our excess wealth with those less fortunate than ourselves. In fact we and our wealth belong to Allah. He is the real owner and we are merely the trustees of His wealth. We do our duty as trustees if we pay Zakah as an obligatory part of Ibadah.
Islam is a complete code of life which includes among other things, the economic side of life. Islam has its own economic principles. Zakah is one of the basic principles of the Islamic economy, based on social welfare and fair distribution of wealth. In addition to the compulsory payment of Zakah, Muslims are encouraged in the Qur'an to make voluntary contributions to help the poor and needy, and for other social welfare purposes. This voluntary contribution is called Sadaqah (Charity).
Through the payment of Zakah, the rich share their wealth with the poor and thus the process of concentration of wealth is checked and fair distribution ensured.
[uwt.org]
Does a kaafir [non-believer] have to pay Zakah? Answer here.