Charles Ellicott Commentary Proverbs 4:23

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

Keep thy heart with all diligence. —Rather, above all things that are to be guarded.

For out of it are the issues of life.—That is, from it comes life (and also death). From it proceed “all holy desires, all good counsels, and all just works,” signs of the life with God within the soul; or, evil thoughts, murders, etc. (Matthew 15:19), the end of which things is death (Romans 6:21).