My reins shall rejoice. The "reins" (kelayoth), kidneys, are regarded as the seat of feeling and sensation (Job 19:27). or of the inner nature generally (Psalms 16:7; Revelation 2:22). I shall rejoice in my very soul when thy lips speak right things; i.
e. when thy heart is so replete with wisdom, thy mind so well instructed as to utter naught but what is true and sensible (Proverbs 8:6). The composition of these two verses is noteworthy, Proverbs 23:15 being parallel to Proverbs 23:16, and Proverbs 23:15 to Proverbs 23:16.
Septuagint, "And thy lips shall linger in words ( ἐνδιατρίψει λόγοις) with my lips, if they be right," which seems to mean, "If thy lips utter what is right, they will gather wisdom from my words and impart it to others."