Biblical Support for a Progressive Tax

President Obama said at the National Prayer Breakfast

If I'm willing to give something up as somebody who's been extraordinarily blessed, and give up some of the tax breaks that I enjoy, I actually think that's going to make economic sense," he said. "But for me as a Christian, it also coincides with Jesus's teaching that “for unto whom much is given, much shall be required [Luke 12:48].”

The president misses the mark in his biblical justification of a biblical justification for a more progressive tax structure because the verse is about personal responsibility and not tax structure.  A similar verse about personal responsibility could be used to suggest that Jesus preferred regressive taxes.

For unto every one that hath shall be given, and he shall have abundance: but from him that hath not shall be taken away even that which he hath.
And cast ye the unprofitable servant into outer darkness: there shall be weeping and gnashing of teeth [Matthew 25: 29-30].

Leaving behind the appropriateness of using the National Prayer Breakfast as a forum to defend the administration’s economic initiatives, the New Testament can be combined with economic theory to justify a government that aids the poor through a progressive tax structure.  Jesus taught to feed the hungry, cloth the naked and visit the sick and afflicted (Mark 12 34-40).  The poor, at least to some extent, cannot feed or cloth themselves so it must be done by those who are not poor. 
The primary lesson of the parable of the widow’s mite (Luke 21:1-4) is that the poor widow who gave only a small amount to the treasury gave more than the rich who gave out of their abundance fits well with the economic theory of the declining marginal utility of money.  The more wealth or money a person has the less a new dollar of wealth or income adds to their wellbeing.  By transferring resources from the wealthy to the less wealth the resources are placed with those who value them more.
The parable of the good Samaritan told of two men who knew that they should have helped another who had been robbed and wounded but did not and a third man who did not have an obligation but did (Luke 10: 30-36).  A progressive tax may force wealthy free-riders who believe that aiding the poor is their social responsibility to meet the obligation that they believe they owe but wish to avoid.  Combining the admonition to care for the poor, the declining marginal utility of money and the free-rider problem, a Christian could build the case for policy to help the poor paid for by a progressive tax system.