Reins
REINS (Heb. kilyâh, Gr. nephros). A word used in the KJV to designate the inward parts. The reins (kidneys) were thought by the Israelites to be the seat of the emotions (Job.19.27; Ps.7.9; Ps.26.2; Jer.17.10). NIV usually translates this word as “mind.” See also Kidneys.
International Standard Bible Encyclopedia (1915)
See Kidneys.