Charles Ellicott Commentary Proverbs 20:27

"The spirit of man is the lamp of Jehovah, Searching all his innermost parts." — Proverbs 20:27 (ASV)

The spirit of man is the candle of the Lord. — The spirit of man, breathed into him at first by the Creator (Genesis 2:7), and afterward quickened and illumined by the Divine Spirit, is the “candle of the Lord,” given to man as an inward light and guide.

Searching all the inward parts of the belly. — That is, of the inmost heart of man; testing all his thoughts, feelings, and desires by God’s law, approving some, condemning others, as they agree with it or not. The word “belly” is equivalent to “heart” or “soul” in Job 15:2; Job 15:15; Job 32:19.