I am re-reading Let the Nations be Glad by John Piper for the class I am taking this summer. The beginning still packs as much punch as when I read it the first time.
Missions is not the ultimate goal of the church. Worship is. Missions exists because worship doesn't. Worship is ultimate, not missions, because God is ultimate, not man. When this age is over and the countless millions of the redeemed fall on their faces before the throne of God, missions will be no more. It is a temporary necessity. But worship abides forever.
Worship is the Goal of Missions:
It's the goal of missions because in missions we simply aim to bring the nations into the white-hot enjoyment of God's glory. The goal of missions is the gladness of the peoples in the greatness of God. "The LORD reigns, let the earth rejoice; let the many coastlands be glad! (Ps 97:1).
Worship is the Fuel of Missions:
Passion for God in worship precedes the offer of God in preaching. You can't commend what you don't cherish. Missionaries will never call out, "Let the nations be glad!" who cannot say from the heart, I rejoice in the LORD . . . I will be glad and exult in you, I will sing praise to your name, O Most High" (Ps 104:34; 9:2).
Missions begins and ends in worship.
John Piper, Let the Nations be Glad, p. 17.