Malachi 3:10 

Bring the full tithe into the storehouse, that there may be food in my house. And thereby put me to the test, says the Lord of hosts, if I will not open the windows of heaven for you and pour down for you a blessing until there is no more need.

What is Tithes

A tithe is defined as a "tenth part". The tithe is "first fruit" of your increase. The principle behind your tithe being your first fruit is you are recognizing God as your source of supply; He is the cause of your prosperity. Therefore, the tithe is not any tenth of one's income; it is the first tenth of one's income. Leviticus 23:10 Speak unto the children of Israel, and say unto them, When ye be come into the land which I give unto you, and shall reap the harvest thereof, then ye shall bring a sheaf of the first-fruits of your harvest unto the priest.