- The topic title is a little 'tabloid' I'll admit, but actually more literal than you'd think:
A thought - or should I say memory - from my active JW days came to me, and that was the often mentioned 'fact' that Jehovah is the God who "tries our heart and kidneys". This was a very common expression used at meetings while I was growing up. Not sure if it was more common in my country and language than in yours. The expression comes from the Bible of course, where in several scriptures, God is mentioned as the one who searches and tries our heart and kidneys. At least this used to be the case in older translations.
This of course was used as a figurative way of getting across how God is searching a person's inner qualities. Jehovah would for instance - if we were asked if all non-JWs would be killed in Armageddon - "search people's hearts and kidneys" to see if they were worthy of survival, so we couldn't say for sure.
The heart as an organ is still to this day used in a figurative way, to express feelings of love, hurt, excitement etc. The kidneys however - not so much (not at all actually, as far as I know). The closest I guess, would be that we will sometimes say we have "a gut feeling" about something.
But why were our kidneys used to signify our inner thoughts; out innermost being, in the Bible? Was it purely figurative, and only used because the kidneys are 'buried' so deep inside us? Interestingly, a lot of modern translations has substituted 'kidneys' (as is the word in the original manuscripts) with 'mind' or 'soul'. I wanted to find out about all this, based on my memory of the expression's usage in the congregation, and so I did a Google search. And I found some very interesting articles. I found more than I had anticipated, actually, and it took it in another direction than I had thought of at first. Which made me find it interesting and wanting to make a topic out of it.
First, an article that should be interesting whether you believe the Bible is the inspired word of God or not (a 'harmless' article, in other words):
http://jasn.asnjournals.org/cgi/content/full/16/12/3464
It's rather long, and if you don't want to read it all, you can read only the Abstract, but I would recommend at least browsing through it all. It should give you a few insights on how and why the kidneys were thought of as some kind of special organs in biblical times, and perhaps not just used figuratively.
Then, an article that perhaps takes it a bit further, and in a slightly different direction; Why does the Bible not mention the brain at all, when several other organs are mentioned? Why for instance, were kidneys and other organs specifically singled out for animal sacrifice, and not the brain? This is also briefly touched upon in the first link.
http://www.infidels.org/library/magazines/tsr/1993/1/1brain93.html
Well - I just find it all interesting. This thread doesn't really ask or answer any questions; I just wanted to share what I found to be an interesting topic.