We should serve God to the best of our abilities within our vocations. God will care for His Church. One cannot emphasize enough “the utter dependence of the church on her Lord,” because her trust in Him is her greatest strength.
God uses the gospel to bring us to faith, to keep us in the one true faith, and to perfect our faith. (Hebrews 12:2). His one gospel does all that. Therefore, those called to distribute God’s gospel in word and sacrament should work to deliver only that gospel. No other “gospel” or human wisdom should be sought, because only God can grow His Church. (Galatians 1:8).
With Might of Ours Can Naught Be Done
No man or creature is able by any thoughts, wisdom, or abilities of his own to advance and maintain the church. In this matter, therefore, neither power nor might nor protection, with which we may console ourselves and on which we may rely, is to be sought from the world.
On the contrary, this task rests entirely and completely in the hands of God alone. He must maintain the church through His divine power, as in fact He has done constantly and marvelously from the beginning in the midst of great weakness, divisions caused by sects and heretics, and persecutions brought on by tyrants. The control of the church is entirely His own, although He commits the office and ministry to men whom He would require and employ to dispense His Word and Sacrament. Therefore every Christian, especially he who is in this office of ministering to others, should make it his sole purpose faithfully to serve God in the sphere into which He has called and placed him and to carry out whatever he has been commanded to do.
But the care as to where and how the church may continue and be maintained against the devil and the world is to be referred entirely to the Lord. He has assumed the entire responsibility for this task and has thereby divested us of all care so that we may be certain that the church will stand and endure. For if the cause of the church were to depend on the counsel, power, and will of man, the devil would soon subvert and overthrow it with his power.
— What Luther Says, Volume I, compiled by Ewald Plass,
Concordia Publishing House, 1972. Page 283.