God requires the tithe was on the "increase" (Deut. 14:22) - the net income, not the gross. It was after deducting such costs as initial capital investments and wages paid to employees. God also authorizes the State to tax success at a low, common, fixed rate, with the combined taxes of all branches of the State at less than the tithe (I Sam. 8:15, 17). The State's tax should also be on the net income. The cases in which payments in gross are required by God are small and infrequent: 1) The firstfruits offering: It was small enough to be carried by a man who walked to Jerusalem. 2) The poor were paid out of gross production when they gleaned. 3) A payment was required for the firstborn (Num. 18:15-17). 4) When the nation was numbered, all men over age 20 who were eligible to serve in the armed forces paid half a shekel to the priests (Exo. 30:12 ). Therefore the State should not confiscate land or equipment from someone who makes no income in a bad year, and likewise, the State should not charge a head or poll tax.
- Gary North, Leviticus: An Economic Commentary 109-10 (1994), at http://www.garynorth.com/freebooks/docs/a_pdfs/gnlv.pdf.