I'll discuss the biblical allusions here, in reference to a powerful motif of the novel. A Separate Peaceis focused around a single, life-changing act: a push from a tree. It is a literal, physical fall. Yet it is also a symbolic, metaphorical fall, in the biblical sense. Finny's fall from the tree reflects humanity's fall from grace, & the birth of original sin.
The reference to Lazarus implies some kind of resurrection or return. Of course, Lazarus was raised from death by Christ 3 days after his entombment. So comparing someone to Lazarus means they've made some kind of comeback. Perhaps they've been out of someone's life for a long time, & their return is as if they've risen from the dead.
The ten commandments reference would most likely suggest a comparison to rules or guidelines for behavior. It may be used to emphasize how egregiously someone has erred, by showing that mistake in a biblical context. It may also show that mistake to be one of morality or ethics, as opposed to a simple issue of legality.
Finally, the allusion to the garden of Eden is the most important for this novel. As I previously stated, the idea of "the fall" is central to the text; thus, the garden represents the past to which the boys can never return. It's the paradise that they will never reach. Once Gene pushes Finny from the tree, their stay in the "garden" of their friendship is over. This becomes the context for their relationship throughout the novel.