"Above all else, guard your heart, for it is the wellspring of life!" Proverbs 4:23
See that your chief study is about your heart: that there, God's image is planted; that there, His interests are advanced; that there, the world and flesh are subdued; that there, the love of every sin is cast out; that there, the love of holiness grows.
"I, the Lord, search the heart and examine the mind!" Jeremiah 17:10