Dietrich Bonhoeffer was a German Lutheran pastor, theologian, anti-Nazi dissident, and founding member of the Confessing Church. In his second dissertation Act and Being he argued that “not all roads appear blocked to the eschatology of apocatastasis.” In his Sanctorum Communio, Bonhoeffer made the stronger claim:
“The strongest reason for accepting the idea of apocatastasis would seem to me that all Christians must be aware of having brought sin into the world, and thus aware of being bound together with the whole of humanity in sin, aware of having the sins of humanity on their conscience. Justification and sanctification are inconceivable for anyone if that individual believer cannot be assured that God will embrace not only them but all those for whose sins they are responsible.” (Dietrich Bonhoeffer in Sanctorum Communio)
Though not embracing the belief in a final universal restitution as a theological doctrine, Bonhoeffer seems to have come close at affirming at least the possibility that all will eventually come to faith in Christ.
Also see Joseph McGarry’s article “Dietrich Bonhoeffer and Apocatastasis: A Challenge to Evangelical Reception“.