Pardon if I make a couple of points.
In ref to the NT....
-The widow who gave her mite was not giving a tithe, she was giving everything. It was a fine thing that she did, but her example does not support a requirement on everyone to give everything, or any specific amount which varies from what she gave.
- It was not - as far as we know - the whole church in Acts that held everything in common. It was only the church in Jerusalem of which this was said. The normal pattern in the NT Church was that those who had, gave,,, and those who needed, received.
In ref to the OT.
- Abraham tithed on the spoils of war (OK, next time I go to war and loot a town or two, I'll tithe on that.)
- Israelites were not commanded to tithe on income, but on the produce of the land. The land which was the "Promised Land",, also a spoil of war, held as being given to them directly by God. Yes, I am aware that Israel was primarily an "agrarian" society, yet it had tradesmen (such as carpenters) artisans and various professions, and yet no-where are these people commanded to tithe on their income of the fruit of their hands. Only the fruit of the land. I do not consider this to be an absolute answer to the issue of tithing, but it should make us thoughtful.
- We have no known descendants of Levi to whom we may bring our tithes.
- It is a rare church in which we might obey the commandment to eat our own tithe before the Lord.
Also, as a farmer I attempted to follow the biblical tithe for some years. Which is a tithe on my turnover, not my income. To put it bluntly, I was not blessed, and ceased tithing when the options available to me were to cease tithing, or rob men by not paying my bills.
Note that I do not make doctrine from my experience, but experience did cause me to re-examine the scripture.
No support for tithing in the NT.
No support for tithing by gentile wage-earners in the OT.
A couple of other thoughts.
A tithe is not a way of buying God's favour ... yet it would be if God automatically blessed us in return.
A tithe would not be a gift if God automatically gave back to us as much or more than we gave to him.
A tithe is not a gift if it is paid as result of an obligation. To be a gift it must be free of that.
Regards......... Peter