"I speak after the manner of men because of the infirmity of your flesh

From Romans 6:19:
Ἀνθρώπινον λέγω διὰ τὴν ἀσθένειαν τῆς σαρκὸς ὑμῶν.

Barth, Epistle to the Romans, paperback edn 1968 (London: OUP, 1933), p. 220-221.

I say, 'ye are' and 'ye stand'. I contrast freedom and slavery. In using such language, however, I speak after the manner of man. We know that all such direct and non-paradoxical descriptions of the invisible and existential human status are definitions of the indefinable. We know that, in daring to use such language, we are entering the twilight of religious romanticism, in which sin and grace, faith and unbelief, take concrete form and become things which some men 'have' and others 'have not'; which some men 'are' and others 'are not'. But we know that the passage from death to life by the power of the resurrection, the freedom from sin and the service to righteousness, may be assigned to no known person. We know that the names of those who may validly be thus described are written only in the book of life. We know that the domain of grace has no existence or non-existence that may be observed; that it is not the property of this or that man; that it does not belong to Children or to Socialists or to the Russian Nation or to the German People, or to Dostoevsky! or to Kutter! And yet we boldly employ this language, the language of romanticism, because it is impossible to describe the immediacy of divine forgiveness except by means of parables drawn from human immediacy. Owing to the infirmity of the flesh, since men's ears are inadequately tuned to the truth, any avoidance of such words as 'existence' or 'possession' necessarily obscures and weakens understanding of the reality of forgiveness. Men must not be permitted to remain spectators, otherwise they will be unable to apprehend the con-version which God effects. It is vital that the possibility of an objective knowledge of God should be wholly eradicated from our minds, because it is only when the perception breaks upon us that we ourselves--each one of us--has been forgiven by Him, that it is proved that we can neither know sin nor commit it. We think we know what we are about when we dare to use this direct language. It is a necessity for the preacher, but it lays him open to very severe criticism. Broken men, we dare to use unbroken language. We must not forget that we are speaking in parables and after the manner of men. We must remember that what is spoken in faith must also be heard in faith, and that grace must be both proclaimed and received as grace, that is, as the observed but invisible establishing of men in God. This warning must be carefully borne in mind when we come to the words which follow.