From Piper Book "Making God Supreme in Missions"

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, therefore, is the fuel and 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). “Let the peoples praise you,
O God; let all the peoples praise you! Let the nations be glad and sing for
joy!” (Ps. 67:3–4).
But worship is also 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.


If the pursuit of God’s glory is not ordered above the pursuit of
man’s good in the affections of the heart and the priorities of the
church, man will not be well served, and God will not be duly honored.