How is the story of Moses from the Bible symbolic with regard to Huck?
The story of Moses symbolizes Huck's journey from boy to man; from poor and downtrodden to rich and a member of proper society who wields power and influence.
Moses's story is symbolic for Huck's story in that they both have to deal with abusive paternal figures. Ramses, Moses's brother and the Pharaoh, exiles Moses after he tries to convince him to free the Hebrew slaves, while Pap, Huck's drunken father, locks him up when Huck refuses to give him access to his gold.
Huck, like Moses, communicates with God; Moses is more literal with the burning bush from his story, but it symbolically represents how Huck communes with God through his time spent on the river and out in nature.
Moses's story is symbolic for Huck's in that they both have tenuous friendship that develop and hinder their destinies. Moses's is with his adoptive older brother, Ramses, who never listens to Moses's ideas. Huck's is with Jim, Miss Watson's runaway slave who gets Huck into trouble along his journey south.
The story of Moses symbolizes Huck's own story -they both travel down a river and, after much experience in proper society (one in Ancient Egypt, the other 1840's American South), come to a realization that they do not agree with the slavery of their respective time periods, taking unpopular action to do what they think is morally right.