The Soul in Christianity

Can anyone recommend a standard, even defining, source for the view of the soul within Christianity? I’m sure Augustine qualifies to some degree. Are there a few others that people would recommend?

While I grew up Roman Catholic, as with many concepts, a lot of this was not clearly defined or (obviously) sourced to particular thinkers. I do want to acknowledge a traditional Christian view of the soul when speaking about it in the Golden Dawn. Suggestions would be welcome.