Beloved Germans! Buy while the vendor is at the front door, make hay while the sun shines and the weather is good, and make use of God's gracious Word while it is still among us. For you should know that God's gracious Word is a swiftly passing downpour, which will not return to where it once rained down. It came to the Jews - but it passed on from them and now they have nothing. Paul brought it to the people of Greece - but it has also passed on from them and they are now controlled by the Turks. Rome and the Latin-speaking lands had it as well - but now it has passed from them and they have the Pope. Likewise, you Germans should not think that you will have access to God's gracious Word forever, for neglect and contempt of it will lead it to pass also from you.
From To the Councilmen of All Cities in Germany, That They Establish and Maintain Christian Schools (1524) WA 15:32.4-13. My own free translation.
a) This is a rich sermon illustration which can lead the preacher to other concrete images. Melanchthon expressed a similar thought somewhere that I read once, but I have not since been able to track it down.
b)Lutheran dogmatics, with its (understandable) anti-Calvinistic polemic, has been concered to stress the universality of grace. Has it given sufficient attention to this thought? Then again, some of the 17th C. Lutheran orthodox used a similar illustration to argue precisely for the universality of grace, in that all peoples had once had access to the Gospel in some form, although it had since passed from them.
c)Pity the pastors who must minister in a time when the gracious Word of God is receding into the distance:
The Sea of Faith
Was once, too, at the full, and round earth's shore
Lay like the folds of a bright girdle furled.
But now I only hear
Its melancholy, long, withdrawing roar,
Retreating, to the breath
Of the night-wind, down the vast edges drear
And naked shingles of the world.
From 'Dover Beach' by Matthew Arnold