Tithing, biblically is in the Old and New Testament all the way back to Abraham. (Genesis 14:18-20). It's a tenth, the first and best 10% that we create, harvest or earn. In modern times this is normally part of earned income. But, another thing that comes out of this, is that it's a way to worship God. God tells us to trust Him and He will bless us in all we do.
If tithing is a way you want to worship, click the link below to give online now.