The phrase the full assurance of faith” occurs in Heb_10:22. “Full assurance” is found also in Heb_6:11, “the full assurance of hope,” and in Col_2:2, “the full assurance of understanding.” The word rendered “full assurance” may mean no more than “fulness,” as the Revised Version renders it in Hebrews. Lightfoot, however, decidedly holds to “full assurance,” saying “for such seems to be the meaning of the substantive wherever it occurs in the New Testament.” In 1Th_1:5 the Greek word occurs with the adjective “much,” so that “fulness” is an impossible translation there.
The word “assurance” has obtained a somewhat narrow theological use, if not even a controversial meaning. The more common word now is certainty, as in the Genevan Version of the Bible at 1Th_1:5, “in much certaintie of persuasion.” But a better equivalent is certitude. It is no longer possible, perhaps, to preserve the distinction between certitude or assurance and certainty, but it is at least worth while seeing what it is.
1. Certitude is a quality or aspect of a particular psychological state, or, as we say ordinarily, of a frame of mind. Certainty, on the other hand, is a quality of propositions; we speak of it currently as attaching to this or that statement. Though, of course, the “frame of mind” is induced by a “certain” proposition, the distinction between certitude and certainty is none the less real.
Certainty is an experience and not merely an impression, it is an assurance of something. We know, not that we feel somehow, but that we feel something. It connotes not only our certitude as its subjective side, but an objective worth. Certitude is valuable according to the certainty, the certain thing, it carries at its heart —which is in it but not of it.
The introductory passage in St. Luke’s Gospel contains in the original a little museum of Greek words, denoting the processes and results of proof in relation to Christianity, and they are substantially represented in our own version. The Evangelist distinguishes between what we now term certitude—or the belief of the mind—and certainty, or the solid reality of the facts or truths believed in;—the one an internal state, the other an external fact, fitted to be the basis of faith. He speaks of things which are “surely believed,” and then of the “certainty” or safe reality of the things so believed in. He adds that with the object of causing Theophilus to know (or rather thoroughly to know) this certainty, he was about to write a fresh and orderly discourse founded on the testimony of eye-witnesses and ministers of the word of God, who could not be mistaken. as to what they had seen or heard. [Note: Edward White, On Certainty in Religion, 3.]
2. Certitude, then, is a state of mind. Generally it is the repose that follows upon our assent to the truth of a statement. After much doubt and, it may be, many misgivings we acknowledge the certainty of a political programme, of an ethical or religious system, or of some philosophic code. The resultant state of mind while it lasts—it may be rudely shaken or it may terminate abruptly—excludes all denial, all doubt, and, at least, all the more harassing difficulties which tend to make our ordinary judgments rock and sway. The mind rests, calmly convinced of the “truth,” undisturbed by the possibilities of criticism or future discovery.
There was an old saint in far-away days—such a one, we can imagine, as was the Venerable Bede in the midst of his young students—who lived a life of such purity and serenity that his younger comrades marvelled. The wonder grew upon them so greatly, that at length they resolved to approach the master, and ask to be told the secret of this purity, this peace. They came one day, and said, “Father, we are harassed with many temptations, which appeal to us so often and so strongly, that they give us no rest. You seem to be untroubled by these things, and we would learn the secret. Do not the temptations that harass our souls appeal to you? Do they never come knocking at the door of your heart?” The old man listened, and smiled, and said, “My children, I do know something of the things of which you speak. The temptations that trouble you do come, making their appeal to me. But, when these temptations knock at the door of my heart, I answer, The place is occupied.’ ” [Note: T. F. Lockyer, Religious Experience, 94.]
3. The permanence of this state of mind depends ultimately upon the certainty of that which brings certitude. It is like hope. For hope, however deep its yearning, would be a poor friend of man were it not for the certainty to which it looks. For the certainty, however veiled, is there, and is the supreme justifier of every pure and holy hope that has ever dwelt in a human heart. Hope is not a blind and spectral figure in an empty world. It strains its eyes to see behind the clouds the glorious sun which is actually, eternally, there. And what that glorious sun is we know. The anchor of our hope entereth into that which is within the veil, whither the Forerunner is for us entered, even Jesus. That is the certainty. There is life at the heart of things because Christ is there; and we can say more. The certainty which justifies hope is not wholly veiled. He is here also; and hope has its facts beside it if only it always knew. For is this not the supremely memorable and historic fact with which our hopes and fears alike have all to do? “God so loved the world, that he gave his only-begotten Son, that whosoever believeth in him should not perish, but have everlasting life.”
The thing we are sure of will settle the nature of our certainty who are sure, and the thing we are most sure of will determine the nature of ourselves. The nature of certainty about the last things is not to be found by any amount of psychology, but by the nature of the revelation which emerges in the psychology—the sure word of prophecy. Psychology is a mere science of observation or experiment; and science can never give us reality, nor certainty about it. [Note: P. T. Forsyth, The Principle of Authority, 42.]
4. But as a rule no distinction is observed between certainty and certitude, either in theology or in Christian experience. Professor Olin Curtis in his manual of The Christian Faith defines certainty in this way: Christian certainty is that personal, moral assurance which a Christian man, in organic relation with the Christian brotherhood, has more and more profoundly, first and most vitally of the reality of his spiritual life in Christ, and then of the reality or truth of the objects and events and doctrines bound up with that life in Christ.
