Albert Barnes Commentary Proverbs 4:23

"Keep thy heart with all diligence; For out of it are the issues of life." — Proverbs 4:23 (ASV)

Better, as noted in the margin, that is, with more vigilance than people use over anything else. The words that follow carry on the same analogy. The fountains and wells of the East were watched over with special care. The heart is such a fountain; out of it flow the “issues” of life. Shall we let those streams be tainted at the fountainhead?