All of scripture testifies of the importance of the heart, ringing a clarion call to all of God's people to incline their hearts to the Lord. The word of God is sown in our hearts. The love of God is shed abroad in our hearts. Jesus dwells in our hearts.
Salvation aims at the heart, as do the fiery darts of the wicked one.
While all of hell is endeavoring to capture the same, bringing them down to perdition.