It is not we who can sustain the Church, nor was it our forefathers, nor will it be our descendants. It was and is and will be the One who says: “I am with you always, even unto the end of the world.” As it says in Hebrews 13: “Jesus Christ, yesterday, and today, and forever.” And in Revelation 1: “Which was, and is, and is to come.” Verily He is that One, and none other is or can be.
For you and I were not alive thousands of years ago, but the Church was preserved without us, and it was done by the One of whom it says, ‘Who was’, and ‘Yesterday’.
Again, we do not do it in our life-time, for the Church is not upheld by us. For we could not resist the devil in… the sects and other wicked folk. For us, the Church would perish before our very eyes, and we with it (as we daily prove), were it not for that other Man who manifestly upholds the Church and us. This we can lay hold of and feel, even though we are loath to believe it, and we must needs give ourselves to the One of whom it is said, ‘Who is’, and ‘Today’.
Again, we can do nothing to sustain the Church when we are dead. But He will do it of whom it is said, ‘Who is to come’ and ‘Forever’. And what we must needs say of ourselves in this regard is what our forefathers had also to say before us, as the Psalms and other Scriptures testify, and what our descendants will also experience after us, when with us and the whole Church they sing in Psalm 124: “If the Lord himself had not been on our side, when men rose up against us,” and Psalm 60: “O be thou our help in trouble, for vain is the help of man.”
… May Christ our dear God and the Bishop of our souls, which He has bought with His own precious blood, sustain His little flock by the might of His own Word, that it may increase and grow in grace and knowledge and faith in Him. May He comfort and strengthen it, that it may be firm and steadfast against all the crafts and assaults of Satan and this wicked world, and may He hear its hearty groaning and anxious waiting and longing for the joyful day of His glorious and blessed coming and appearing. May there be an end of this murderous pricking and biting of the heel, of horrible poisonous serpents. And may there come finally the revelation of the glorious liberty and blessedness of the children of God, for which they wait and hope in patience. To which all those who love the appearing of Christ our life will say from the heart, Amen, Amen.
~ Martin Luther (Weimarer Ausgabe 54, 470 and 474 f.). Cited by Karl Barth in the preface to Church Dogmatics I/2.