David’s heart was fixed (Psalms 57:7, 108:1) not upon what appeared to be good, but on that which is truly perfect, righteous, and holy. The appearance of some might be comely in countenance and in the manner of their behavior toward the life they live, but the life they express will be determined by whom their eye is fixed upon.
The Lord explicitly tells Samuel (1 Samuel 16:7) not to look on the countenance or stature because the Lord looks upon the heart. When your heart is fixed on peace, the Lord looks on the order of His own mind. When your heart is fixed on perfect righteousness, the Lord looks down on that which sustains you (Isaiah 59:16). When your heart is fixed on holiness, the Lord looks on what he has made you to be through grace.
If you keep your eye single, it will be full of light to reveal that which stands against you in darkness. You have all the fullness in Him in whom the Father is well pleased (Colossians 1:19). When your eye is fixed on the fullness, the life you inherit will consist of all that makes up Who the Son is. We are conformed to His image through beholding the very substance of fullness the Father invested which is now in the Body of Christ (Ephesians 1:23).
By the Blood we are reconciled unto Him wherein all fullness dwells (Colossians 1:20; Ephesians 2:13). Every area of our lives will reap the effectual substance we behold in the fullness of Him that fills all in all.