delight. Note the double delight (Isaiah 42:1.Matthew 3:17; Matthew 3:17).
will. good pleasure.
within. in the midst.
heart. bowels: i.e. my inward parts.
Related Commentaries of Psalms 40:8
Psalms 40:8
8 I delight to do thy will, O my God: yea, thy law is withind my heart.