How is the will of God done in heaven? Sadly? Burdensomely? Begrudgingly? No! It is done gladly! If I then pray, “Thy will be done on earth as it is in heaven,” how can I not be motivated by a desire to be glad? It is a contradiction to pray for the will of God to be done in my life the way it is done in heaven, and then to say I am indifferent to whether I am glad or not. When the earth rejoices to do His will and does it perfectly, His will shall be done on earth as it is in heaven.
John Piper