I'm first going to share something I know you've already heard. But stick with me...
The tithe was connected to the land. Only Produce derived from the seed of Israel whether from field, tree or herd. If one wanted to tithe money, it wasn't a tithe because one could not consume money. The tithe had to be eaten before the Lord in a time of celebration, in a community God approved for that year (Deut.14:23). Also, if one wanted to give money or other goods, it was called an heave offering. It was also a free will offering. A tithe was ten percent of one's harvest,
not income.
Leviticus 27:30, "And all the tithe of the land, whether of the seed of the land, or of the fruit of the tree, is the LORD’S: it is holy unto the LORD."
Deuteronomy 14:22, "Thou shalt truly tithe all the increase of thy seed, that the field bringeth forth year by year."
Leviticus 27:32, "And concerning the tithe of the herd, or of the flock, even of whatsoever passeth under the rod, the tenth shall be holy unto the LORD."
Deuteronomy 14:23, "And thou shalt eat before the LORD thy God, in the place which he shall choose to place his name there, the tithe of thy corn, of thy wine, and of thine oil, and the firstlings of thy herds and of thy flocks; that thou mayest learn to fear the LORD thy God always."
In fact, if one studies Judaism and rabbinical writings one will quickly learn that the only two classes of people ordered to tithe are the landowners and the Levites within the boarders of Israel. The stranger, orphan, and widow received tithes from the local landowners, and were also exempted from tithing. Others like, fishermen, carpenters and all other non farmers and craftsmen of any occupation are exempt from tithing as well if they did not own and farm their land.
The disciples, who were fishermen, weren't required to tithe.
Jesus, prior to his ministry, was a carpenter. Carpenters were not required to tithe.
That brings us to your position.
Your position focuses on the notion of God desiring our "increase" be it related to the land such as livestock, grain, and/or produce... or monetary increase.
If that were truly so... why didn't God seek or require a tithe of such "increase" in the Bible? Why were carpenters, stone masons, fishermen, merchants, traders, weavers, and other professions exempt from tithing??? If God never changes (like you stated)... then aren't all non-farming professions exempt from tithing today? And doesn't this prove that God wasn't concerned with any "increase"...unless it was in relation to farming and its connection with the "
holy land"?
So, I believe your position in regards to the claim that God never changes, and that God desires our "increase" actually defeats itself when compared to what the "Bible" defines as tithe-able increase and those professions that were exempt from tithing. If God never changes, nor would His definition of "increase", nor would His definition of exempted classes and professions.