Spiritual joy is: The settled conviction that God sovereignly controls the events of life for the believers’ good and His glory. Spiritual joy is not an attitude dependent on chance or circumstance. It is the deep and abiding confidence that regardless of one’s circumstances in life, all is well between the believer and the Lord. No matter what difficulty, pain, disappointment, failure, rejection, or other challenge one is facing, genuine joy remains because of that eternal well being established by God’s grace in salvation. Thus, Scripture makes it clear that the fullest, most lasting and satisfying joy is derived from a true relationship with God. It is not based on circumstances or chance, but is the gracious and permanent possession of every child of God.
John MacArthur