Princes Don't Pay Tax

Monsignor Moran had an interesting insight pertaining to paying taxes, referring to Matt 17: 22-27.  In this gospel, the temple tax collectors wanted Jesus to pay the temple tax and Jesus has Peter catch a fish and take the coin out of the fish's mouth to pay the tax.

But do princes of a kingdom pay tax?  No, their subjects do.  The people pay taxes to the king, but the sons of the king aren't expected to pay. They're exempt.

Well...isn't Jesus a prince?  Isn't His Father a King?