When Jesus uses the Aramaic term mammon to refer to wealth, he is giving it a personal and spiritual character. When he declares, “You cannot serve God and mammon” (Matt. 6:24), he is personifying mammon as a rival god.

In saying this, Jesus is making it unmistakably clear that money is not some impersonal medium of exchange. Money is not something that is morally neutral, a resource to be used in good or bad ways depending solely upon our attitude toward it. Mammon is a power that seeks to dominate us.

from The Challenge of the Disciplined Life