Here is an excerpt:
Proverbs 4:23 says to keep thy heart with all diligence; for out of it are the issues of life. Our hearts are like fortresses under attack, and we must guard them accordingly. Most people will diligently guard their fortunes and homes, which are of temporal value, but they are very careless about guarding that which is of eternal value their very souls! In this work, originally titled A Saint Indeed, John Flavel (1627 1691) looks at what it means to keep the heart, how to keep the heart, and why keeping the heart is the greatest business of every person.
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