Preparation frees us to worship in heart and mind while we serve. Preparation frees us to appropriately respond to the movements of the Holy Spirit in the service. Preparation frees us to engage and care for the people of the church. The lack of preparation binds our heart and mind to practicality, putting us in danger of quenching the Spirit.
Whatever you do, work heartily, as for the Lord and not for men. Colossians 3:23 (ESV)
Whatever you find to do with your hands, do it with all your might. Ecclesiastes 9:10a (ESV)