But the holy orders and true religious institutions established by God
are these three: the office of priest, the estate of marriage, the
civil government. [See Large Catechism, 4th Commandment, 158, and the
Augsburg Confession, Article XVI] All who are engaged in the clerical
office or ministry of the Word are in a holy, proper, good, and
God-pleasing order and estate, such as those who preach, administer
sacraments, supervise the common chest, sextons and messengers or
servants who serve such persons. These are engaged in works which are
altogether holy in God’s sight.
Again, all fathers and mothers who regulate their household wisely and
bring up their children to the service of God are engaged in pure
holiness, in a holy work and a holy order. Similarly, when children
and servants show obedience to their elders and masters, here too is
pure holiness, and whoever is thus engaged is a living saint on earth.
Moreover, princes and lords, judges, civil officers, state officials,
notaries, male and female servants and all who serve such persons, and
further, all their obedient subjects — all are engaged in pure
holiness and leading a holy life before God. For these three
religious institutions or orders are found in God’s Word and
commandment; and whatever is contained in God’s Word must be holy, for
God’s Word is holy and sanctifies everything connected with it and
involved in it.
Above these three institutions and orders is the common order of
Christian love, in which one serves not only the three orders, but
also serves every needy person in general with all kinds of benevolent
deeds, such as feeding the hungry, giving drink to the thirsty,
forgiving enemies, praying for all men on earth, suffering all kinds
of evil on earth, etc. Behold, all of these are called good and holy
works. However, none of these orders is a means of salvation. There
remains only one way above them all, viz. faith in Jesus Christ.
For to be holy and to be saved are two entirely different things. We
are saved through Christ alone; but we become holy both through this
faith and through these divine foundations and orders. Even the
godless may have much about them that is holy without being saved
thereby. For God wishes us to perform such works to his praise and
glory. And all who are saved in the faith of Christ surely do these
works and maintain these orders.
(AE 37:364-365)
Note that neither the three broad categories (churchly, domestic, and
civil) that Luther describes, nor the examples he gives, are meant to be
mutually exclusive. Our church Treasurer supervises the common chest,
but also holds other churchly responsibilities, as well as
responsibilities in the other categories.