From Martin Luther’s “Large Catechism”

“I believe that there is on earth a holy lit­tle flock and com­mu­nity of pure saints under one head, Christ. It is called together by the Holy Spirit in one faith, mind, and under­stand­ing. It pos­sesses a vari­ety of gifts, and yet is united in love with­out sect or schism. Of this com­mu­nity I also am a part and mem­ber, a par­tic­i­pant and co-partner in all the bless­ings it pos­sesses. I was brought into it by the Holy Spirit and incor­po­rated into it through the fact that I have heard and still hear God’s Word, which is the begin­ning point for enter­ing it. Before we had come into this com­mu­nity, we were entirely of the devil, know­ing noth­ing of God and of Christ. The Holy Spirit will remain with the holy com­mu­nity or Chris­t­ian peo­ple until the Last Day. Through it he gath­ers us, using it to teach and preach the Word. By it he cre­ates and increases holi­ness, caus­ing it daily to grow and become strong in the faith and in its fruits, which the Spirit produces.

“Fur­ther we believe that in this Chris­t­ian com­mu­nity we have the for­give­ness of sins, which takes place through the holy sacra­ments and abso­lu­tion as well as through all the com­fort­ing words of the entire gospel. This encom­passes every­thing that is to be preached about the sacra­ments and, in short, the entire gospel and all the offi­cial respon­si­bil­i­ties of the Chris­t­ian com­mu­nity. For­give­ness is con­stantly needed, for although God’s grace has been acquired by Christ, and holi­ness has been wrought by the Holy Spirit through God’s Word in the unity of the Chris­t­ian church, yet we are never with­out sin because we carry our flesh around our neck.

“There­fore every­thing in this Chris­t­ian com­mu­nity is so ordered that every­one may daily obtain full for­give­ness of sins through the Word and signs appointed to com­fort and encour­age our con­sciences as long as we live on earth. Although we have sin, the Holy Spirit sees to it that it does not harm us because we are a part of this Chris­t­ian com­mu­nity. Here there is full for­give­ness of sins, both in that God for­gives us and that we for­give, bear with, and aid one another.”

(Book of Con­cord, p. 438)