| Barnes' Notes on the Bible The teacher rejoices when the disciple's heart Proverbs 23:15 receives wisdom, and yet more when his lips can utter it. Reins - See Job 19:27 note.
Gill's Exposition of the Entire BibleYea, my reins shall rejoice,.... Which is only another phrase expressive of the same thing, and confirming the greatness of joy on the above occasion; not only his heart rejoiced, which was affectionately concerned for his son, near which he lay, the desires of which were frequently drawn out for his good, but his reins also; the seat of the afflictions rejoiced at it; showing how vehement, sincere, and hearty the joy was; when thy lips speak right things; as they will, when the heart is wise; things agreeably to right reason, to the Scriptures of truth, the oracles of God; to the law and to the testimony; to the Gospel of Christ, and the doctrines of it; and such things as are savoury, pleasant, and profitable, and minister grace to the hearers. The Targum is, "when my lips speak right things;'' see Proverbs 8:6.
Geneva Study BibleYea, my reins shall rejoice, when thy lips speak right things.
Wesley's Notes 23:16 My reins - I shall rejoice with all my soul.
Jamieson-Fausset-Brown Bible Commentary16. my reins-(Compare Ps 7:9).
Matthew Henry's Concise Commentary23:12-16 Here is a parent instructing his child to give his mind to the Scriptures. Here is a parent correcting his child: accompanied with prayer, and blessed of God, it may prove a means of preventing his destruction. Here is a parent encouraging his child, telling him what would be for his good. And what a comfort it would be, if herein he answered his expectation! 17,18. The believer's expectation shall not be disappointed; the end of his trials, and of the sinner's prosperity, is at hand. | 
