New Defender's Study Bible Notes
26:2 my reins and my heart. “Reins and heart” commonly are used as figures for the thoughts and emotions”; as representative the innermost being, just as the reins (that is kidneys) and heart are vital internal organs of the body. The word “reins” is an archaic term for “kidneys,” and the Hebrew word is commonly translated “kidneys” when referring to the actual physical organ. See note on Psalm 7:9.
26:3 thy truth. See note on Psalm 25:10. In the Hebrew text, “mercy” and “lovingkindness” are the same word.