Faith and Obedience of a Piece

In chapter 2 of Bonhoeffer's The Cost of Discipleship, these two propositions are set forth: 1) "only he who believes is obedient," and 2) "only he who is obedient believes."  Bonhoffer then asserts what surely is in fact biblically the case:

It is quite unbiblical to hold the first proposition without the second.  We think we understand when we hear that obedience is possible only where there is faith.  Does not obedience follow faith as good fruit grows on a good tree?  First, faith, then obedience.  If by that we mean that it is faith which justifies, and not the act of obedience, all well and good, for that is the essential and unexeptionable presupposition of all that follows.  If, however, we make a chronological distinction between faith and obedience, and make obedience subsequent to faith, we are divorcing the one from the other--and then we get the practical question, when must obedience begin?  Obedience remains separated from faith.  From the point of view of justification it is necessary thus to separate them, but we must never lose sight of their essential unity.  For faith is only real when there is obedience, never without it, and faith only becomes faith in the act of obedience.

This all seems to be biblically sound stuff, except that last bit about faith only becoming faith in the act of obedience.  That sounds like obedience creates faith.  I don't find this in Scripture.  With many of the reformers, I believe that faith does have the priority.  Obedience always flows from faith, theo-logically, actually, necessarily.  But the rest of this quotation is undoubtedly dead on. 

I'm realizing that as Bonhoeffer says many useful and stirring things, he often overstates his case and lacks biblical nuance.  Nevertheless, the first 50 pages or so of The Cost of Discipleship would be healthy compulsory reading for the membership class in a local church, lest we give assurance to would-be disciples too soon.  With the invitation to come to Christ should also come the words of Lk. 14:28: "count the cost."  Otherwise we may simply be multiplying the spurious conversions in our churches.  And there is already too much of that.