Why should this great question have been preceded by the other? Probably to make the disciples feel more distinctly the chaotic contradictions of the popular judgment, and their own isolation by their possession of the clearer light. He wishes them to see the gulf opening between them and their fellows, and so to bind them more closely to Himself. This is the question the answer to which settles everything for a man. It has an intensely sharp point. We cannot take refuge from it in the general opinion. Nor does any other man's judgment about Him matter one whit to us. This Christ has a strange power, after nineteen hundred years, of coming to each of us, with the same persistent interrogation on His lips. And to-day, as then, all depends on the answer which we give. Many answer by exalted estimates of Him, like these varying replies which ascribed to Him prophetic authority, but they have not understood His own name for Himself, nor drunk in the meaning of His self-revelation, unless they can reply with the full-toned confession of the apostle, which sets Him far above and apart from the highest and holiest.
As to the contents of the confession, it includes both the human and the divine sides of Christ's nature. He is the Messiah, but He is more than what a Jew meant by that name; He is 'the Son of the living God,' by which we cannot indeed suppose that Peter meant all that he afterwards learned it contained, or all that the Church has now been taught of its meaning, but which, nevertheless, is not to be watered down as if it did not declare His unique filial relation to the Father, and so His divine nature. Nathanael had burst into rapturous adoration of Jesus as 'the Son of God' at the very beginning; and the disciples' glad confidence, which cast out the fear of the dim form striding across the sea, had echoed the confession; all had heard His words, 'No man knoweth the Father but the Son.' So we need not hesitate to interpret this confession as in essence and germ containing the whole future doctrine of our Lord's divinity. True, the speaker did not know all which lay in His words. Do we? Do we not see here an illustration of the method of Christian progress in doctrine, which consists not in the winning of new truths, but in the penetrating further into the meaning of old and initial truths? The conviction which made and makes a Christian, is this of Peter's; and Christian growth is into, not away from, it.
As to the results, they are set forth in our Lord's answer, which breathes of delight, and we may almost say gratitude. His manhood knew the thrill of satisfaction at having some hearts which understood though partially, and loved even better than they knew. The solemn address to the apostle by his ancestral name, gives emphasis to the contrast between his natural weakness and his divine illumination and consequent privilege. The name of Peter is not here bestowed, but interpreted. Christ does not say 'Thou shalt be,' but 'Thou art,' and so presupposes the former conferring of the name. Unquestionably, the apostle is the rock on which the Church is built. The efforts to avoid that conclusion would never have been heard of, but for the Roman Catholic controversy; but they are as unnecessary as unsuccessful. Is it credible that in the course of an address which is wholly occupied with conferring prerogatives on the apostle, a clause should come in, which is concerned about an altogether different subject from the 'thou' of the preceding and the 'thee' of the following clauses, and which yet should take the very name of the apostle, slightly modified, for that other subject? We do not interpret other books in that fashion. But it was not the 'flesh and blood' Peter, but Peter as the recipient and faithful utterer of the divine inspiration in his confession, who received these privileges. Therefore they are not his exclusive property, but belong to his faith, which grasped and confessed the divine-human Lord; and wherever that faith is, there are these gifts, which are its results. They are the 'natural' consequences of the true faith in Christ, in that higher region where the supernatural is the natural. Peter's grasp of Christ's nature wrought upon his character, as pressure does upon sand, and solidified his shifting impetuosity into rock-like firmness. So the same faith will tend to do in any man. It made him the chief instrument in the establishment of the early Church. On souls steadied and made solid by like faith, and only on such, can Christ build His Church. Of course, the metaphor here regards Jesus, not as the foundation, as the Scripture generally does, but as the founder. The names of the twelve apostles of the Lamb are on the foundations of the heavenly city; and, in historical fact, the name of this apostle is graven on the deepest and first laid. In like subordinate sense, all who share that heroic faith and proclaim it are used by the Master-builder in the foundations of His Church; and Peter himself is eager to share his name among his brethren, when he says 'Ye also, as living stones.'