Proverbs 4:23 NLT [23] Guard your heart above all else, for it determines the course of your life.

The heart is the place in which the process of self-consciousness is carried out, in which the soul is at home with itself, and is conscious of all its doing and suffering as its own”

As the engine in a motor vehicle determines its function, so the heart also determines our function and also our destinies. All we ought to be; is determined by what we are inside. It is our inner being that's demonstrated on the outside.