thy fountain: i.e. thine own wife. Compare Proverbs 5:16.
rejoice with. get thy joy with. Some codices, with Septuagint, Syriac, and Vulgate, read "in" instead of "with".
Related Commentaries of Proverbs 5:18
Proverbs 5:18
18 Let thy fountain be blessed: and rejoice with the wife of thy youth.