Or KIDNEYS. The Hebrews often make the reins the seat of the affections, and ascribe to them knowledge, joy, pain, pleasure; hence in Scripture it is said that God searches the heart and tries the reins.
the kidneys, the supposed seat of the desires and affections; used metaphorically for "heart." The "reins" and the "heart" are often mentioned together, as denoting the whole moral constitution of man (Ps 7:9; 16:7; 26:2; 139:13; Jer 17:10, etc.).
The kidneys, used symbolically for the inward thoughts and feelings. Ps 7:9; 16:7; 26:2; 139:13; Pr 23:16; Jer 12:2; 17:10; 20:12; La 3:13; Re 2:23. The word translated 'reins' in Isa 11:5 is elsewhere translated 'loins.'