A Solitary Christian is a Contradiction

James Bannerman, The Church of Christ, Vol. 1, pp. 19-21:

We may assert, therefore, that that Christian society which we call the Church of Christ is a society formed by Divine appointment, even did we see in it nothing more than a body of men brought together by the constraint of the same faith and same affections wrought in them by the Spirit of God. But there is much more than this intimated in Scripture, on which we ground the assertion that the Church of Christ is a divinely instituted society. There are express commands in Scripture, leaving the believer no alternative in the matter, and requiring him to unite together with other believers in the outward and public profession of his faith before the world. He is not left at liberty to hide that faith within his own heart, and himself to remain alone and separated from his fellow-believers. It is the office of the Christian society to be a witness, by means of an outward and public profession, for Christ on the earth; and it is not a matter of choice, but of express obligation, with a Christian man to join with others in that public profession. The command is "to confess Christ before men;"1 and upon the ground of the command, then, is laid the foundation of a society, each member of which is called upon, whether he will or will not, to lift up a public testimony for his Saviour jointly with other believers; and that public profession is one to be made not merely with the lips, uniting with others in a common declaration of the faith believed. The outward ordinances of the Christian society are so framed and devised as to be themselves a significant profession of faith on the part of those who join in them; and communion in ordinances is with Christians not a matter of choice, but of express command. Christ has judged it proper to appoint that His disciples shall be solemnly received into His Church by the initiatory rite of baptism; so that the very entrance of life, or, at all events, the admission into the Christian society, shall be itself a public testimony to Him. He has enjoined the public and open commemoration of the central and most characteristic doctrine of His faith, by the celebration, at stated intervals, of the Lord's Supper; and as often as the first day of the week returns, the disciples are commanded "not to forsake the assembling of themselves together," but to unite in the outward and joint worship of the Saviour. In short, in the whole divinely appointed institutions and ordinances of the Christian society we see the provision made for, and the obligation laid upon, His disciples to be joined together into one outward body, and to form a common society of professing believers. That community is one, therefore, of Divine institution; and in the duty laid upon them, not as a matter of choice, but of express command, to become members of it, we see the ordinance of God for the existence and permanent establishment of a Church on earth. A solitary Christian is seen to be a contradiction in terms, if you view merely his faith as a principle of affinity naturally destined to draw to it the faith of other believers. A solitary Christian is worse than a contradiction, he is an anomaly, standing out against the express institution of God, which has appointed the fellowship of believers in one Church, and made provision in its outward ordinances for their union and edification. The Christian society is a kingdom, set up by express Divine appointment, and differs from every other society on earth in this remarkable fact, that the builder and maker of it is God.

1 Matt. x. 32; Luke xii. 8; John xii. 42; Rom. x. 9.