"God Money" sounds like a modern-day version of Mammon, the biblical personification of greed as a false idol.
"Mammon" was an old Hebrew word that simply meant wealth.
Chapter 6 of the Book of Matthew implores the followers of Jesus not to follow the path of greed: "Lay not up for yourselves treasure upon earth, where moth and rust doth corrupt, and where thieves break through and steal: But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal: For where your treasure is, there will your heart be also. No one can serve two masters, for either he will hate the one and love the other; or else he will be devoted to one and despise the other. You can not serve both God and Mammon."
The memorable phrasing of that last line has led many to personify Mammon, viewing Mammon not merely as the abstraction "wealth" but as an actual demon-god representing greed and selfishness. (In John Milton's Paradise Lost, for example, Mammon is depicted as a fallen angel who worships only treasure.)
Nail me up against the wall
This is an interesting lyric; depending on how you hear it, it could evoke two very different ideas: the desire for sexual domination and the resignation to a Christ-like crucifixion.
It all depends on what "nail" means; in either sense, the verb is vividly or even disturbingly descriptive. Is the singer demanding to be nailed up against the wall just as Christ was nailed up on the cross, perhaps sacrificing himself to offer the world redemption from the corruption of "God Money"?
Or is this "nailing" instead a coarse sexual metaphor? What kind of worship are we talking about here? The uncomfortable confusion of the sexual and the spiritual is perhaps the song's key lyrical element.
Head like a hole
black as your soul
This one's a bit hard to wrap your brain around. Black and darkness as evil and emptiness is a common theme in our culture.
There are plenty of examples in our culture—both highbrow and lowbrow—of the idea that darkness equals evil. The black cat as bad luck, for example. In Shakespeare, Macbeth refers to his desires to kill King Duncan as "black and deep desires."
In fact, "black" seems to be entirely synonymous with evil in Macbeth, as when he describes the witches he meets in Act IV as "secret, black, and midnight hags." Biblically there's a sense of darkness as void and emptiness, literally contrasting with the light of God.
God Money's not concerned about the sick among the pure
God Money, let's go dancing on the backs of the bruised
God Money is here described as the diametric opposite of Jesus Christ.
Jesus was known as a healer, performing miracles to heal the afflicted. There are dozens of passages in the New Testament that describe Jesus as a healer. Healing was a huge part of Jesus' ministry, according to Matthew, Mark, Luke, and John.
One story, in Luke 7:1-10 and Matthew 8:5-13, describes the example of Jesus healing the slave/servant of a Centurion because he had such great faith in the Lord that he believed that his word alone would heal him.
God Money, on the other hand, simply doesn't care. He is pro-sickness, and it seems that, with "dancing on the backs of the bruised," the pain of others is key to the hedonistic qualities he possesses.
You know who you are
This final lyric seems to turn the whole song around; a lyric that had seemed confessional suddenly turns accusatory.
The line makes the narrative of the rest of the song a mockery of those greedy folks who apparently know who they are.