I don't use religious texts as a basis for making decisions, but I recognize that a lot of people do.
I've heard some of them cite Matthew 26:11 as a reason for not giving. Days before Jesus' execuation, a woman pours expensive perfume on him, and Judas complains that the perfume could have been sold to raise money for the poor. Jesus answers,
The poor you will always have with you, but you will not always have me.
Today I learned that this, like many of Jesus' sayings, was a reference to the Torah. Jesus and his audience would have been familiar with the full Deuteronomy passage:
There will always be poor people in the land. Therefore I command you to be openhanded toward your brothers and toward the poor and needy in your land.
Not quite the "don't bother helping the poor" message the Matthew passage is often used to further.