Reins

Reins - (Easton's Bible Dictionary)

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.).

Reins - (Webster's 1828 Dictionary)

REINS, n. plu. [L. ren, renes.]

1. The kidneys; the lower part of the back.

2. In Scripture, the inward parts; the heart, or seat of the affections and passions. Psa 73.