The goal of William Blake's London is to expose the aristocracy's subjugation of London's lower classes during the late 18th century. "Runs in blood down palace walls" is another image from the poem that indicates to the reader the aristocracy's tyranny of the lower class. Bloodshed is also indicated by other words such as "slay", "massacre", and "crush". The poet wants the reader to understand that the lower class is oppressed by the upper class. Blake uses biblical allusions to explain this phenomenon. For example, he says that "Princes rule by grace" which means that the prince receives his power from God instead of being awarded to him by people. He continues by saying that "Tyrants rule by fear" which refers to the fact that the prince rules over the lower class by terrorizing them. Finally, Blake claims that "Families line their pockets with your pain" which means that the nobility steals money from the poor through extortion and robbery. These are just some examples of how Blake shows oppression in London. If you read between the lines of the poem, you will see that Blake is criticizing the monarchy for allowing slavery to exist in Britain. He also believes that religion has been used by the aristocracy to keep the lower class subservient rather than encourage them to be free.