From Peter Forsyth, The Work Of Christ; Cf. The Work of Christ at Amazon

In the days of our fathers Christian belief was more solid within the Church than it is now; and the defending and expounding of Christianity, more especially the defending of it, had to concern itself with outsiders – outside the Church, and outside Christianity very often. Today our difficulties have changed; and a great part of our exposition must keep in view the fact that some of the most dangerous challenges of Christianity are found amongst those who claim the Christian name. There are those who have a very real reverence for the character of Jesus Christ, and they can speak, and do speak, quite sincerely, with great devotion and warmth and beauty, about Christ, and about many of the ideas that are associated with apostolic Christianity. All the same, they are strongly and sometimes even violently, antagonistic to that redemption which is the very center of the Christian faith; and they make denials and challenges which are bound to tell upon the existence of that faith before many generations are over. We do not take the true measure of the situation unless we realize that the thing which is at stake at this moment is something that will not affect the present generation, but is sure to affect two or three generations hence. Those who are concerned about Christianity on the largest scale today are concerned with what may be its position and its prospects then. The ideas at the center of the Christian faith are too large, too deep and subtle, to show their effects in one age; and the challenge of them does not show its effect in one generation or even in two. Individuals, society, and the Church, indeed, are able to go on, externally almost unaffected, by the way that they have upon them from the past; and it is only within the range of several generations that the destruction of truths with such a comprehensive range as those of Christianity takes effect. Therefore it is part of the duty of the Church, in certain sections and on certain occasions, to be less concerned about the effect of the Gospel upon the individual immediately, or on the present age, and to look ahead to what may be the result of certain changes in the future. God sets watchmen in Zion who have to keep their eye on the horizon; and it is only a drunken army that could scout their warning. We are not only bound to attend to the needs and interests of the present generation; we are trustees for a long future, as well as a long past. Therefore it is quite necessary that the Church should give very particular attention to these central and fundamental points whose influence, perhaps, is not so promptly prized, and whose destruction would not be so mightily felt at once, but would certainly become apparent in the days and decades ahead.

That is why one feels bound to invite attention, and to press attention, upon points concerning which it may very easily be said, “These are matters that do not concern my faith and my piety; I can afford to let these things alone.” Perhaps A, B, and C can, and X, Y, and Z can; but the Christian Church cannot afford to let these things alone. The Church carries the individual amid much failure of his faith; there is a vicarious faith; but what is to carry the Church if its faith fail? Remove concern from these things, and the effect of the collective message of the Church to the great world becomes undermined. Then the world must look somewhere else than to the Church for that which is to save it. That is some apology for dwelling upon points which many people would say were simply theological and were outside the interest of the individual Christian. Theology simply means thinking in centuries. Religion tells on the present, but theology tells on the religion of the future and the race.

Moreover, there are always natures among Christian people who refuse, and properly refuse, to remain satisfied with superficial experiences or current views of their faith. They are bound by the spirit that moves within them – by the kind of temperament God has given them they are bound to penetrate to the heart, to the depths of things. Their work does not immediately pay; and while they grind in their mill the Philistines mock and the libertines jeer. But it would be a great misfortune if the whole of the work of the Church were measured by the standard which is so necessary in the world – the standard of what will immediately pay, or promptly tell. It is, of course, a great thing to go back upon the history of Christianity, and to point out to ourselves and to our people the great things that Christianity has done in the course of history. But you cannot rest Christianity upon that. You can only rest Christianity upon Christ Himself, and His living presence in the New Humanity. You can put the matter in this way. You can ask, On what did the Christianity rest of those who believed in the very first years of the Church’s life? They had no results of Christianity before them. They had no history of the Church before them. They had not the glorious story of Christian philanthropy before them, nor the magnificent expansion of Christian doctrine, nor the enormous influence of the Christian Church and its effect upon the course of the world’s history. On what did they rest their faith? That upon which they rested their faith must be that upon which we rest our faith when we come to a real crisis, and are driven into a real corner. It thus becomes necessary to go into the deep things of God as they are revealed to us by the Holy Spirit, through His inspired apostles, in Christ and His Cross.