Search the Heart and Test the Kidneys
This strange metaphor might actually make sense.
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Which anatomical organ do you associate with intelligence and reasoning? You most likely thought of the brain. What about emotions and passion? You probably thought of the heart…or the brain again. Although these questions seem like no-brainers, that wasn’t always the case. The ancient Israelites would not have thought of either the brain or the heart when asked this question. They would have thought of the kidneys.
The connection of kidneys to consciousness is seen in Jeremiah 17:10 in which the word kelayot (כְּלָי֑וֹת) is translated to “the mind” and “the feelings”. However, it also means “kidneys”. As strange as it looks today, this figure of speech is on par with expressions that deal with listening to your heart or going with your gut. It isn’t entirely clear how this metaphor came to be or when it fell out of favor, but the translation of kelayot as “mind” or “feelings” shows that the Bible is full of literary devices that shouldn’t always be taken at face value.
Despite many changes in language and science through the ages, this metaphor might make more sense than we think. The literal function of the kidneys is to expel wastes and to maintain water and electrolyte balance in the body. Without this physical process, we would die. Likewise, God wants His people to filter out toxic ideas and behaviors and expel them as they would expel urine or feces.
The filtration function of the human conscience prevents the soul from becoming poisoned by negative influences. Having moments when you ask “Should I be doing this?” or “Is this really ethical?” are signs that your spiritual kidneys are working. Having connections to both morals and logical reasoning, the testing of one’s proverbial kidneys is necessary to live a healthy life as a Christian and as a person.