For Christian holiness, or the holiness common to Christendom, is found where the Holy Spirit gives people faith in Christ and thus sanctifies them, Acts 15 [:9], that is, he renews heart, soul, body, work, and conduct, inscribing the commandments of God not on tables of stone, but in hearts of flesh, II Corinthians 3 [:3].
First, the holy Christian people are recognized by their possession of the holy word of God. To be sure, not all have it in equal measure, as St. Paul says [I Cor. 3:12–14]. Some possess the word in its complete purity, others do not. Those who have the pure word are called those who “build on the foundation with gold, silver, and precious stones”; those who do not have it in its purity are the ones who “build on the foundation with wood, hay, and straw,” and yet will be saved through fire.
This is the principal item, and the holiest of holy possessions, by reason of which the Christian people are called holy; for God’s word is holy and sanctifies everything it touches; it is indeed the very holiness of God, Romans 1 [:16], “It is the power of God for salvation to every one who has faith,” and I Timothy 4 [:5], “Everything is consecrated by the word of God and prayer.” For the Holy Spirit himself administers it and anoints or sanctifies the Christian church with it.
Second, God’s people or the Christian holy people are recognized by the holy sacrament of baptism, wherever it is taught, believed, and administered correctly according to Christ’s ordinance. That too is a public sign and a precious, holy possession by which God’s people are sanctified. It is the holy bath of regeneration through the Holy Spirit [Titus 3:5], in which we bathe and with which we are washed of sin and death by the Holy Spirit, as in the innocent holy blood of the Lamb of God. Wherever you see this sign you may know that the church, or the holy Christian people, must surely be present.
Third, God’s people, or Christian holy people, are recognized by the holy sacrament of the altar, wherever it is rightly administered, believed, and received, according to Christ’s institution. This too is a public sign and a precious, holy possession left behind by Christ by which his people are sanctified so that they also exercise themselves in faith and openly confess that they are Christian, just as they do with the word and with baptism.
Fourth, God’s people or holy Christians are recognized by the office of the keys exercised publicly.395 That is, as Christ decrees in Matthew 18 [:15–20], if a Christian sins, he should be reproved; and if he does not mend his ways, he should be bound in his sin and cast out. If he does mend his ways, he should be absolved. That is the office of the keys. Now the use of the keys is twofold, public and private. There are some people with consciences so tender and despairing that even if they have not been publicly condemned, they cannot find comfort until they have been individually absolved by the pastor.
Fifth, the church is recognized externally by the fact that it consecrates or calls ministers, or has offices that it is to administer. There must be bishops, pastors, or preachers, who publicly and privately give, administer, and use the aforementioned four things or holy possessions in behalf of and in the name of the church, or rather by reason of their institution by Christ, as St. Paul states in Ephesians 4 [:8], “He received gifts among men …”—his gifts were that some should be apostles, some prophets, some evangelists, some teachers and governors, etc. The people as a whole cannot do these things, but must entrust or have them entrusted to one person. Otherwise, what would happen if everyone wanted to speak or administer, and no one wanted to give way to the other? It must be entrusted to one person, and he alone should be allowed to preach, to baptize, to absolve, and to administer the sacraments. The others should be content with this arrangement and agree to it. Wherever you see this done, be assured that God’s people, the holy Christian people, are present.
Sixth, the holy Christian people are externally recognized by prayer, public praise, and thanksgiving to God. Where you see and hear the Lord’s Prayer prayed and taught; or psalms or other spiritual songs sung, in accordance with the word of God and the true faith; also the creed, the Ten Commandments, and the catechism used in public, you may rest assured that a holy Christian people of God are present. For prayer, too, is one of the precious holy possessions whereby everything is sanctified, as St. Paul says [I Tim. 4:5]. The psalms too are nothing but prayers in which we praise, thank, and glorify God. The creed and the Ten Commandments are also God’s word and belong to the holy possession, whereby the Holy Spirit sanctifies the holy people of Christ. However, we are now speaking of prayers and songs which are intelligible and from which we can learn and by means of which we can mend our ways.
Seventh, the holy Christian people are externally recognized by the holy possession of the sacred cross. They must endure every misfortune and persecution, all kinds of trials and evil from the devil, the world, and the flesh (as the Lord’s Prayer indicates) by inward sadness, timidity, fear, outward poverty, contempt, illness, and weakness, in order to become like their head, Christ. And the only reason they must suffer is that they steadfastly adhere to Christ and God’s word, enduring this for the sake of Christ, Matthew 5 [:11], “Blessed are you when men persecute you on my account.” They must be pious, quiet, obedient, and prepared to serve the government and everybody with life and goods, doing no one any harm.
No people on earth have to endure such bitter hate; they must be accounted worse than Jews, heathen, and Turks. In summary, they must be called heretics, knaves, and devils, the most pernicious people on earth, to the point where those who hang, drown, murder, torture, banish, and plague them to death are rendering God a service. No one has compassion on them; they are given myrrh and gall to drink when they thirst. And all of this is done not because they are adulterers, murderers, thieves, or rogues, but because they want to have none but Christ, and no other God. Wherever you see or hear this, you may know that the holy Christian church is there, as Christ says in Matthew 5 [:11–12], “Blessed are you when men revile you and utter all kinds of evil against you on my account. Rejoice and be glad, for your reward is great in heaven.” This too is a holy possession whereby the Holy Spirit not only sanctifies his people, but also blesses them.
These are the true seven principal parts of the great holy possession whereby the Holy Spirit effects in us a daily sanctification and vivification in Christ, according to the first table of Moses. By this we obey it, albeit never as perfectly as Christ. But we constantly strive to attain the goal, under his redemption or remission of sin, until we too shall one day become perfectly holy and no longer stand in need of forgiveness.
All quotes from: Luther, M. (1999, c1966). Vol. 41: Luther's works, vol. 41: Church and Ministry III (J. J. Pelikan, H. C. Oswald & H. T. Lehmann, Ed.). Luther's Works (Vol. 41,). Philadelphia: Fortress