Tithing did occur before the Mosaic Law was given. There are actually three kinds of tithing in the Bible…the way Abraham did it, the way Jacob did it, and the way that the Jews did it.
Abraham (Genesis 14):
Abraham tithed to Melchizadek…he gave a tenth of the spoils of war. If we’re to tithe as Abraham did, we should give a tenth of the spoils of war to the king. Since that’s all the information we have, that’s all we should presume about the passage.
Jacob (Genesis 28):
Jacob tithed directly to God out of gratitude…if you want to tithe out of gratitude, that’s between you and God. Since that’s all the information we have, that’s all we should presume about the passage.
As I’ve written elsewhere, the tithe was a debt owed by Jews to God with specific instructions on who could collect it, how it was to be used, etc. If we’re to tithe as the Jews did, we need to read and understand and follow the instructions given to the Jews. If your pastor has done his homework, he can tell you that this isn’t happening. Other than the examples of Abraham and Jacob, everything we read in the Bible about tithing is directed at Jews. Unless your pastor is willing to put himself under the entire Mosaic Law, there’s no Scriptural reason for him to say that you should tithe. Abraham tithed to the king and Jacob tithed to God Himself. Where do we find instructions that Christians should tithe to the church? There aren’t any.
I do believe in giving.
I believe that Christians should be very generous, and that the New Testament example is to give cheerfully and generously to those in need as the Holy Spirit leads us. Anyone who tells you that the Bible tells Christians to tithe is either ignorant or lying, because it simply isn’t there. Hey, if someone wants to give ten percent of their income to the church, that’s their business…but if someone says “God wants Christians to tithe to the church” I want to know which book and which verse they say tells them that. What could be more reasonable than that?
Here’s what I’d suggest:
Get a pen and paper and then ask your pastor for a list of Bible verses that teach Christians to tithe. If he doesn’t have a list for you, ask him if he will make one for you. Whatever he tells you, write it down and look it up. See for yourself what the Bible says, and compare what you think with what the pastor says. If (after doing your homework) you disagree with your pastor, go to him respectfully and ask to talk about it. His response will go a long way toward understanding what sort of spiritual leader he is.