GROSS OR NET?
The Biblical tithe always came from the NET; never from the gross.
Genesis 14:20 (KJV) And blessed be the most high God, which hath delivered thine enemies into thy hand. And he gave him tithes of all.
Hebrews 7:4 (KJV) Now consider how great this man was, unto whom even the patriarch Abraham gave the tenth of the spoils.
Genesis 14:24 (KJV) Save only that which the young men have eaten….
Abram gave to King Melchizedek a tenth of the spoils THAT WERE LEFT after subtracting out the food that had already been eaten from the spoils. Therefore, Abram gave a tenth from the NET spoils, not the gross spoils.
The Levitical tithe:
Leviticus 27:30 (KJV) 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.
Leviticus 23:22 (KJV) And when ye reap the harvest of your land, thou shalt not make clean riddance of the corners of thy field when thou reapest, neither shalt thou gather any gleaning of thy harvest: thou shalt leave them unto the poor, and to the stranger: I am the LORD your God.
Nehemiah 10:37 (KJV) And that we should bring the firstfruits of our dough, and our offerings, and the fruit of all manner of trees, of wine and of oil, unto the priests, to the chambers of the house of our God; and the tithes of our ground unto the Levites, that the same Levites might have the tithes in all the cities of our tillage.
We start with the gross (total) crops, subtract the amount left at the corners and any gleaning of the harvest, and also subtract the firstfruits that were taken to the priests, and then tithe from the net amount.
Leviticus 27:32 (KJV) 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 (KJV) 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.
We start with the gross, or total number of new born animals during the year, remove the firstlings that were to be eaten at the festival, and tithe from the net by tithing the last one out of every ten counted under the rod.