The Law of Moses
One thing is for sure - tithing is definitely a subject brought up multiple times in the Mosaic Law. In the Old Testament, we see a system set in place full with sacrifices, rituals, ceremonies, offerings, and priests. There was much discussion about ceremonial cleansing and holiness. It was clear that God introduced the concept of certain individuals mediating between him and everyday people, and at some level, we can attribute all of this to the simple reality that he was perfect and they were not. And there is one other enormous reality of their day and time that warranted such a ritualistic, disciplined system of worship...Jesus had not yet come!
One practice that was in full effect for the Israelites under the old covenant was the tithe. So what can we observe about this component of their religious life and community?
1. Before, and upon, entering the Promised Land, Moses sets out clear responsibilities for one of the tribes known as the Levites. They are the priestly tribe, responsible for the work at the Tent of Meeting. "The Levites are to be responsible for the care of the tabernacle of the Testimony" (Numbers 1:52-54). Because the Levites were set apart for special duties, they were not to receive an inheritance of land as they moved in to Canaan. All other tribes were given a specific allotment of land. Rather than being in charge of their own dwelling like everyone else, the Levites had to be concerned, in a very serious manner, with "the Lord's dwelling" so to speak. Thus, one of the tithes instituted helped serve the purpose of providing food for the Levites, and giving them something to sacrifice to the Lord in offerings. It was a tithe given by the other Israelites and received by the Levites.
2. Another important aspect of Israelite worship was that of national festivals and celebrations. God instituted events such as Passover and the Feast of Unleavened Bread, the Feast of Weeks or Firstfruits, the Feast of Trumpets (which was their version of a New Year's party), and more. Remembering how God had intervened in their lives was a crucial part of Israelite worship, so these festivals became an instrumental way of shaping the attitude of repentance and gratitude to solidify the bond that God desired to have with his children. The Bible tells us that one of the tithes required of Israel was intended to be use to provide for these corporate events.3. Another significant and repeated word of instruction in the Law of Moses is that a tithe should be received so that, in addition to the Levites, the aliens, fatherless, widows, and poor would be sufficiently taken care of. People facing these hard circumstances were to be comforted and looked after appropriately. Not doing so seemed to elicit God's anger with his own people.
**Some Scriptures you might want to look up include Leviticus 27:30-33, Numbers 18 (verses 21 & 24 specify Levitical roles), Deuteronomy 14:22-29, and Deuteronomy 26:12-15.
To conclude, if you read through the referenced passages above, then you may begin to make some additional observations without having to read anything into the text. For instance, it will probably stand out to you (from the Bible text itself and the notes above) that more than one tithe is commanded. There were annual tithes and triennial tithes, and you may also note that they went to different "causes." Many scholars agree that this certainly puts our "ten percent" rule under scrutiny. In fact, some argue that with the combined tithes, the Israelites were required to give more like 23% of their produce or income! I am not personally familiar with any church teaching this kind of tithing.
Finally, I will end on something that should be easy for us all to agree on. Whatever, or however, the tithe was given and received, there was a clear emphasis on giving the best, or first, of what you had. Regardless of where we fall on this debate, I think this should be a point we all walk away with firmly in mind and heart.