Reins

Reins (from the Latin renes, kidneys) is an archaic English term used in the KJV to translate the Hebrew kelayot (kidneys) when referring to the seat of the deepest emotions, thoughts, and moral sensibility. In ancient Israelite physiological psychology the kidneys (reins) were understood to be the location of the deepest self — equivalent to what we might call conscience or the innermost being. Psalm 7:9 speaks of God as the one who tests the hearts and minds (reins); Psalm 16:7 describes the reins instructing the psalmist in the night; Psalm 26:2 invites God to examine his heart and reins; Revelation 2:23 uses the same imagery when the risen Christ declares he is the one who searches minds (kidneys) and hearts. Modern translations typically render kelayot as mind or inner parts.