Luke 20:19-26

Luke 20:19-26 
English Standard Version (ESV)

  There's a debate in church circles about whether you should tithe on the gross or net income.  Dave Ramsey's got an article on it.  Some church people will debate whether it's robbing God or not.  You can make a strong case for either -- the Biblical writers didn't anticipate the 1861 Revenue Act, when 3% of all incomes over $800 were taxed (Wouldn't it be nice to go back to that?), pointing the way to the passing of the 16th Amendment in 1909 that would codify the income tax.  And so because it's not spelled out, there's solid arguments for either.
  Here, the Pharisees are hoping to trap Jesus, either for being an insurrectionist and telling the people not to pay taxes to Rome, or for pledging allegiance to Rome and turning the people against him. 
  What Jesus is talking about here, and always, is that all things belong to God, and if we lose that fact in the debate over minor things, we'll miss the major things.  What the tithe is all about is remembering that all gifts come from God, and that we would have nothing without God.  In an agrarian culture, the tithe was intended to be the first 10% of the harvest.  One didn't collect everything and then partition aside 10% once it was clear how much was there.  The first 10% was set aside, and only then did the rest flow towards other uses.  The gifts of the harvest were the gifts of God, and the tithe was intended to direct the heart to glorify God for the good gifts that are received.
  And so decide how you will give.  Be intentional and decide upfront, because if you wait until you have gathered everything and give out of the leftovers, it's not the same, because then you give in to the heart's tendency to try and secure ourselves first, and then reach out to God.  I'm not telling anyone not to pay their rent with the first 10%, but I do think you need to be intentional on the front to decide how to give, and then follow through, in whatever way enables your heart to give glory to God and remember that God is the giver of all good gifts and wants to pour blessings upon you.