I'd like to find some references that discuss the concept of kingdom. Not facts about the word usage in the Bible, but more philosophical or abstract. Along the lines of why does God talk about a Kingdom, how is the concept rooted in the nature of God and His creation, why kingdom vs other forms of governance or societal organization etc.
In L4 I can search for the word, but it going to take me hours if not days to wade through all of them, even if I restrict the search to theological manuals/books.
Perhaps someone knows a good resource to start with or can suggest a way to go about searching for this topic in Logos. I have something close to the Scholar's basic library.