Ephesians 3:16-17

Ephesians 3:16 That He would grant you, according to the riches of His glory, to be strengthened with power through His Spirit into the inner man,

Ephesians 3:17 That Christ may make His home in your hearts through faith, that you, being rooted and grounded in love,

We all need to be strengthened into our inner man so that Christ will be able to make His home in our hearts. Our heart is composed of all the parts of the soul -the mind, emotion, and will - plus the conscience, the main part of our spirit. 

Through regeneration, Christ came into our spirit. Subsequently, we should allow Him to spread Himself into every part of our heart. Since our heart is the totality of all our inward parts and the center of our inward being, when Christ makes His home in our heart, He is able to control our entire inner being and supplies and strengthens every inward part with Himself. The secret of Christ making His home in our heart is the stregthening of our inner man. 

- "Life Study of Ephesians" PP785-786