Would anyone else agree that "trying the reins" is a test of self-control? Reins are straps used to control a horse's head. That's my best guess. The bible is kind of confusing to read sometimes. That's why I don't own one.

I have looked up some bible study groups' interpretations of this extract online and here's another way of explaining it: I, the Lord, search the heart; I test inner motivations; in order to give to everyone what his actions and conduct deserve."

"Reins" is the French word for kidneys. Someone got confused - to the point that I even found a silly explanation of how "kidneys" is correct. More modern versions translate the phrase as "examine/test the mind", though chpr's definition of reins is also in the literal translation.

http://brandplucked.webs.com/reinsheartmind.htm *Jeremiah 17:10 - "I the LORD search the heart, [I] try the reins…" This English word, “reins:” Webster’s Seventh New Collegiate Dictionary: Etymology: Middle English, from Anglo-French, from Latin rene; kidneys: the region of the kidneys: the seat of the feelings or passions ATS (American Tract Society) Bible Dictionary - REINS - Or KIDNEYS. The Hebrews often make the reins the seat of the affections, & ascribe to them knowledge, joy, pain, pleasure; hence in Scripture it is said that God searches the heart & tries the reins. Fausset's Bible Dictionary - Reins kelayot. The "kidneys"; the supposed seat of the desires & affections). For "the loins" (halatsaim), Isaiah 11:5. Smith's Bible Dictionary - Reins (i.e. kidneys). In the ancient system of physiology the kidneys were believed to be the seat of desire & longing, which accounts for their often being coupled with the heart. (Psalms 7:9; 26:2; Jeremiah 11:20; 17:10), etc. The International Standard Bible Encyclopedia - REINS - “Derived from Latin "renes" through Old French "reins", has given place in modern English to the word "kidneys". According to Hebrew psychology the reins are the seat of the deepest emotions & affections of man, which God alone can fully know.” In the NT, the word “reins” is found only once. The Greek word used here & found only one time in the entire NT is nephos, which literally means kidneys. In fact, in English we have the words nephritis - a kidney disease, & Nephrology, the diagnosis & treatment of kidney diseases. Even the word “reins” is related to the English word “renal” which refers to the kidneys as in “renal failure”. There appears to be some overlap, but it seems that the "reins" are more restricted to the emotional center of man, while the "heart" is more concerned with the thoughts, though our thoughts can also be accompanied with emotional overtones Will Kinney