Proverbs 4:23 in the World English Bible
Keep your heart with all diligence, for out of it is the wellspring of life.
Context
22 For they are life unto those that find them, and health to all their flesh.
23 Keep thy heart with all diligence; for out of it are the issues of life.
24 Put away from thee a froward mouth, and perverse lips put far from thee.