Charles Ellicott Commentary Proverbs 5:18

"Let thy fountain be blessed; And rejoice in the wife of thy youth." — Proverbs 5:18 (ASV)

Let your fountain ...—As a reward for purity of life, the blessing of a numerous offspring is invoked. (Compare Psalm 128:3, where the wife is a fruitful vine, and the children numerous and flourishing like olive-branches).