Commenting about the upcoming gospel reading about the community being the salt of the earth, Bonhoeffer writes:
"Ye are the salt." Jesus does not say: "You must be the salt." It is not for the disciple to decide whether they will be the salt of the earth, for they are so whether they like it or not, they have been made salt by the call they received. Again, it is: "Ye are the salt," not "Ye have the salt." By identifying the salt with the apostolic proclamation the Reformers robbed the saying of all its sting. No, the word speaks of their whole existence in so far as it is grounded anew in the call of Christ, that same existence which was the burden of the beatitudes. The call of Christ makes those who respond to it the salt of the earth in their total existence.
Of course, there is another possibility--the salt may lose its savour and cease to be salt at all. It just stops working. Then it is indeed good for nothing but to be thrown away. That is the peculiar quality of salt. Everything else needs to be seasoned with salt, but once the salt has lost its savour, it can never be salted again. Everything else can be saved by salt, however bad it has gone--only salt which loses its savour has no hope of recovery. That is the other side of the picture. That is the judgment which always hangs over the disciple community, whose mission it is to save the world, but which, if it ceases to live up to the mission is itself irretrievably lost. The call of Jesus Christ means either that we are the salt of the earth, or else we are annihilated; either we follow the call or we are crushed beneath it. There is no question of a second chance.-Bonhoeffer, The Cost of Discipleship, 1995 Touchstone Books, pp. 116-117
Challenging words for a tradition so hyper-sensitive to notions of works righteousness. Images that Bonhoeffer uses there at the end distress us. Given his situation when the established church accommodates itself to the prevailing culture and then ultimately gives in to Nazi control, whatever the disciples thought they were, by attaching themselves to something other than Christ, adhering to cultural and social mores, their salt had been leached out. They had become something other than salt.
But our saltiness is not supported by our own effort. If it is the call of Jesus that makes us salt, then the community gathered around Jesus will never lose its saltiness completely for Jesus sustains it. We must place our hope in Christ and trust in his preservation of us. Even in the midst of Nazi control, the Church never departed from Germany, the salt remained, giving us the witness of the Confessing Church. Some portion of the community remained to give witness to Jesus and therefore BE salt. Wherever Jesus is, his community will be, and there, we will taste salt.