Rufus wrote: It is perfectly legal. If a church wants to voluntarily place themselves under the headship of the IRS, they are free to do so. If they want to be under the headship of Jesus Christ than they should not sign the document to turn themselves into a 501c3 organization and they should not incorporate (becoming a creature of the state).
Frank wrote: First let me say there are always exceptions to rules but the problem is when we form our biblical understanding using the exception rather than the rule. For instance, if a husband becomes disabled and can't work; should the wife work. Well the answer is yes if they have no other means of income, but then does that mean that the man shouldn't be the provider and the woman shouldn't stay home (or work at home); of course not. Without knowing anything more than what you said in your example, I would say that it is probably wrong that the wife is supporting her husband even if he is in the ministry. In fact, I will say that makes it even more wrong. God never asks anyone to violate His teaching so they can serve Him.