God’s Word earnestly forbids us to enter an office or ministry without a call and an express divine command. Speaking of uncalled prophets, God says: “I have not sent these prophets, yet they ran” (Jer. 23:21). And He threatens them with destruction. Again: “Let none of you suffer as a murderer, a thief, an evildoer, or as a busybody in other people’s matters” (1 Peter 4:15). Or: “We urge you, brethren, that you increase more and more; that you also aspire to lead a quiet life, to mind your own business...as we commanded you” (1 Thess. 4:10-11).
In all these passages the Spirit of God shows us that God has no pleasure in the arrogance of those who take on themselves offices in the church without a legitimate call, for He desires that in His church all things should be done decently and in order. Therefore He appointed some apostles, some prophets, some pastors, some rulers, and some hearers and subjects. By His Spirit God distributes His several gifts and desires that no one should hinder the other in his calling or ministry. Therefore, if there are true ministers or pastors who teach the pure and sound doctrine and profess membership in the true Christian church and are appointed by the church for the ministry, let no private [uncalled] person dare administer the sacraments, even if some fault is to be found with the life of the pastors; for the sacraments are not to be avoided because of the unworthiness of the ministers, as those errorists, the Donatists, alleged, who were thoroughly refuted by Augustine and were rejected by the whole church for valid reasons. For as the worthiness or piety of a minister does not add anything to the sacraments (since its power rests on God’s Word and command), so also a minister’s unworthiness or unbelief does not take anything away from it. As a seal, whether engraved in gold or lead, prints the same picture, so also the sacraments have one nature and power, whether they are administered by believing or unbelieving ministers.
Therefore, a Christian should not easily be misled to remain away from the legitimate ministry, for in this way there soon will arise factions, sects, and schisms, or dissensions. As soon as you separate yourself from the called ministry, you also sever your connection with the church that acknowledges or tolerates such ministers in their office... The state of a minister or pastor has been established and separated from that of the common Christian because there should be certain persons to preach the Gospel and in their office to administer the sacraments, since ordinary Christians must look after their work and support, just as people in general, and it is not given to everyone to teach others. So also [the ministry has been instituted] that the ministers might be well instructed in the pure and sound doctrine and live an upright life and that the Christians might not be tossed to and fro and be carried about with every wind of doctrine. (Who Has the Power, Authority, and Right to Call Ministers?, pp. 32,36; quoted in C. F. W. Walther, Church and Ministry [Saint Louis: Concordia Publishing House, 1987], pp. 188-89).
There can be no doubt that in an emergency, when no duly called
pastor can be obtained, every Christian has the power and is permitted,
according to God’s Word and out of Christian love, to attend to the ministry
of the Word by preaching the divine Word and administering the sacraments. ...
But here we speak of what a Christian may do in an emergency when no godly and
sincere minister of the church may be obtained, for example, when some
Christians are in a place where no appointed pastor is to be had; or when some
Christians, for the sake of the truth, are held captive or are in peril on the
sea; or when some Christians are among the Turks or in the papacy, where there
is no true pastor; or when some Christians are among Calvinists,
Schwenckfelders, Adiaphorists, or Majorists, whom they must avoid as false
teachers; or when some Christians have pastors or ministers who publicly
exercise tyranny and cruelly persecute the sincere confessors of the truth and
thus clearly show that they are not members of the true church, for which
reason conscientious [gottselige] Christians must refrain from
fellowshiping with them so as not to strengthen their tyranny and help condemn
innocent Christians.
In such and similar emergencies, which indeed have often occurred,
when sincere pastors whose teaching and confession are sound and in agreement
with God’s Word cannot be secured, individual laymen and believing Christians
may absolve penitent sinners, comfort the weak with God’s Word, baptize
infants, and administer Holy Communion. In such emergencies a Christian should
not be troubled about being a busybody in another’s business, but he should
know that he is performing a true and due call of God and that his ministry is
just as efficacious as if it were ratified by the laying on of hands for the
office of the ministry in the whole church.
This does not mean that two or three Christians should separate
themselves from the true church, avoid the regular called ministers, and cause
factions, but I say this of emergency cases when either there are no pastors
or those who exist spread false doctrine and so must be avoided. In addition
there is also the emergency that the use of the sacraments cannot be found in
other places. In such cases, every Christian, with the consent of two or
three, is authorized and justified to administer the sacraments and strengthen
the weak in the peril of death. ...
Ministers and pastors have been appointed and separated from ordinary
Christians in order that there might be certain persons who preach the Gospel,
serve the congregation, and administer the sacraments. Christians, like all
other people, must attend to their work and the earning of their daily bread.
It is also not given to everyone to teach others. Finally, pastors must also
be well instructed in pure and sound doctrine and be examples in their way of
life, so that the Christians might not be carried about with every wind of
doctrine. Otherwise, there is no difference between ministers and ordinary
Christians. In the kingdom of Christ the one has no more authority than the
other. From this it also follows that ordinary Christians, in such cases when
no upright minister of the Word is to be had, may preach the Gospel, remit
sins, baptize, and administer the Lord’s Supper. (quoted in Felix Bidembach, Consil. theol., decade 3, cons. 5, p. 383 ff.; quoted in turn in C. F. W. Walther, Church and Ministry, pp. 281-82.)