When people set aside a set portion of their income for the Church, this is known as tithing. Tithing is practiced in both the Jewish and Christian traditions, and some other religions have a form of tithing as well. By tradition, a tithe is classified as 10% of someone's income, although in the modern day, tithing typically represents a much smaller percentage, with one to three percent being more common.
The Old Testament provides ample support for the practice of tithing, although tithing was not widely practiced in the Christian church until almost the seventh century. Before tithing became an integral part of Christian faith, however, Christians still gave generously of their incomes to support the Church and its teachers. For those without money, such donations might take the form of manufactured goods, farmed foods, and various services to support the Church.
In some parts of the world after the seventh century, tithing became an obligation, with all people required to pay tithes. Tithing income was used to support religious officiants, to build churches and other monuments to the faith, and to perform the works of the Church, ranging from sending missionaries to providing food for the poor. The rate of the tithe varied, depending on what was being tithed; farmers might be tithed for grain, for example, while wineries surrendered part of their wine as a tithe. Tithes were stored in a tithing barn for use or sale by the Church and its officials.
The practice of mandatory tithing still exists in some regions; Catholics, for example, are required to tithe in some European countries. Failure to pay at least 1% of your income to the Church is punishable, with the Church being given the legal right to sue people who fail to pay their tithes, unless people testify to the effect that they are leaving the Church. In other regions, tithing is simply encouraged, and in many cases it is tax-deductible, along with other charitable donations.
Tithing doesn't just have to be for Christians and members of the Jewish faith, although it is closely associated with these religions. Agnostics and atheists may choose to set aside a portion of their income for charity to support their communities just as Christians support the Church and its works with tithing. Some people find that dedicating part of their income to charity is very rewarding, as it establishes a connection with the community, and allows people to encourage projects and works which they think are particularly meritorious.