Worship is a way of life. What defines the Christian life?
Am I fulfilling the responsibilities God has given me? God's grace is sufficient that we may live the life He has given us.
The distinction is Psalm 1 is between those who are devoted to the word of God, and the counsel of the wicked, not just belief and unbelief.
A person can believe that they should devote themselves to the word of God and not do it.
True service is in light of God's word. Our motivation for service and worship is God's glory.
God is worshipped when His word is obeyed.
God is served when His word is obeyed.
God's grace is sufficient to live the life He has given us.