Matthew Poole and continuators on Proverbs 3:8

8. It shall be health to thy navel , and marrow to thy bones.

i. e. To thy Body, which is signified by the Navel, which is a noble and useful part of the Body, by which the Infant receives nourishment in the Womb, and which is the ligament or bond by which the bowels, a principal part of the Body, are united together and preserved.

Which is the nourishment and strength of the bones, and a great preserver and prolonger of life, as the decay of it is a chief cause of the weakness and driness and decay of the Body. The sense of the Verse is, This Wisdom or fear of God is not onely useful to the Salvation of the Soul, but also to the health and welfare of the Body, both as it prevents those Diseases and Distempers which are oft procured by sinful Lusts and Passions, and as it giveth us an Interest in all God's promises, and putteth us under the care of his special Providence.

Marginal references: Heb. medicine.; Heb. watering, or moistning.