The Unity of the Church.
I. That all Christians are, in some sense or other, one, in our Lord's eyes, is plain, from various parts of the New Testament. It is to this one body, regarded as one, that the special privileges of the Gospel are given. It is not that this man receives the blessing, and that man, but one and all; the whole body as one man, one new spiritual man, with one accord, seeks and gains it.
II. When asked why we Christians must unite into a visible body or society, I answer (1) that the very earnestness with which Scripture insists upon a spiritual unseen unity at present, and a future unity in heaven, of itself directs a pious mind to the imitation of that unity visible on earth; for why should it be so continually mentioned in Scripture, unless the thought of it were intended to sink deep into our minds and direct our conduct here? (2) But again, our Saviour prays that we may be one in affection and in action; yet what possible way is there of many men acting together, except that of forming themselves into a visible body or society, regulated by certain laws and officers? and how can they act on a large scale and consistently, unless it be a permanent body? (3) I might rest the necessity of Christian unity upon one single institution of our Lord's, the sacrament of baptism. Baptism is a visible rite, confessedly; and St. Paul tells us that by it individuals are incorporated into an already existing body. But if every one who wishes to become a Christian must come to an existing visible body for the gift, it is plain that no number of men can ever, consistently with Christ's intention, set up a Church for themselves. All must receive their baptism from Christians already baptized; and thus we trace back a visible body or society even to the very time of the Apostles themselves. (4) One other guarantee, which is especially suggested by our Lord's words in the text, for the visible unity and permanence of His Church, is the appointment of rulers and ministers, entrusted with the gifts of grace, and these in succession. The ministerial orders are the ties which bind together the whole body of Christians in one; they are its organs, and they are, moreover, its moving principle.
J. H. Newman, Parochial and Plain Sermons,vol. vii., p. 230.
References: Matthew 16:18. S. G. Green, Christian World Pulpit,vol. i., p. 49; L. Abbott, Ibid.,vol. xxxii., p. 362; G. Brooks, Outlines of Sermons,p. 103; J. E. Vaux, Sermon Notes,2nd series, p. 58; E. W. Shalders, Christian World Pulpit,vol. xvi., p. 152; J. C. Jones, Studies in St. Matthew,p. 255; W. Anderson, Discourses,p. 66; C. Kingsley, Village Sermons,p. 309. Matthew 16:18; Matthew 16:19. Expositor,3rd series, vol. iv., p. 1.