For this, therefore, I say that Christ Himself existed not to present us with the supreme spiritual spectacle of history, but to achieve the critical thing in history. The Gospel is an act of God,
gathered in a point but thrilling through history, and it calls for an act, and inspires it. Its preaching must therefore be an act, a “function” of the great act. A true sermon is a real deed. It puts the preacher’s personality into an act. That is his chief form of Christian life and practice. And one of his great difficulties is that he has to multiply words about what is essentially a deed. If you remember what men of affairs think about the people who make set speeches in committee you will realize how the preacher loses power whose sermons are felt to be productions, or lessons, or speeches, rather than real acts of will, struggles with other wills, and
exercises of effective power. The Gospel means something done and not simply declared. For this work Christ existed on earth. And to give this work effect Bible and Church alike
exist. We treat the Church as plastic to that work and its fulfilment, do we not? That is the true Church, and the true form of Church, which gives best effect to the Gospel. So also we must treat the Bible with much flexibility. The test and the trial of all is the grace of God in Jesus Christ, and in Him as crucified. Everything is imperishable which is inseparable from that.
P.T. Forsyth, Positive Preaching and the Modern Mind 22-23
But what does he mean by “flexibility”?