Someone once told me that St. Vincent said something to this effect: We had better love the poor. If we don't, they will never forgive us for the charity we give them.
I've returned to that one from time to time. It suggests to me that not only do we have to examine our motives and examine our consciences around our sins, but around the good things we do as well.
All of us who do charitable service, works of justice, or community organizing need to ask ourselves why we are doing these things on behalf of the poor. Is it because we love them? Or is it because we hate the rich? Or maybe it's because of our righteous indignation at the systemic injustice of this world. Or maybe, God forbid, it's our liberal guilt that motivates us.
Love is the only valid motive for our works of Christian service. Indeed, it's the only valid motive for anything. After all, it's the only motive God has ever known.