In this treatise, the author offers a coherent structure of doctrine as he discusses the fundamental principles and leading applications of the doctrine of the church, primarily those commonly received among Scottish Presbyterians. Bannerman brings to the foreground such important topics as the Church's authority—how it received it and how it wields it—the Church's function, essential nature and peculiar characteristics, and the Scriptural form of church government and its relationship to the State.
Volume One of this two volume work (full title: The Church of Christ: a treatise on the nature, powers, ordinances, discipline, and government of the Christian Church) deals with the nature and power of the Church, containing a lengthy explanation of the Church in its relation to the state, which is arguably one of the best treatments of this topic available. From there it deals with matters in regard to which Church power is exercised (i.e. in regard to doctrine, ordinances, the instrumentality and time of public worship — with a discussion of holy days, Independency, and confessions). Volume Two continues where Volume One left off, providing a lengthy section on the sacraments, covering the parties in whom the right to exercise church power is vested, examining crucial points concerning Christian liberty, comparing the Popish, Prelatic, Independent, Congregational and Presbyterian systems, etc. Nine appendices deal with a wide range of practical topics including union between churches, Church/State relations, ordination, and valuable notes on the literature related to this subject.
Iain Murray, a prominent scholar and co-founder of the Reformed publishing house, The Banner of Truth Trust, has said of The Church of Christ that "for those who wish to study the doctrine of the Church in its several aspects as it was held by the majority of the Reformers, Puritans, Covenanters and leaders of 'The Third Reformation,' it will prove an invaluable textbook."
“The proper party with whom the covenant of grace is made, and to whom its promises and privileges belong, is the invisible Church of real believers. It is this Church for which Christ died.” (Volume 1, Page 30)
“The single thing essential to the being of a Christian Church on earth is the faith or doctrine of Christ.” (Volume 1, Pages 59–60)
“I. In the first place, the Christian Church, in reference to the world in which it is found, is designed and fitted to be a witness for Christ, and not a substitute for Christ.” (Volume 1, Page 83)
“Even in the case of two or three professing Christians, met together for prayer and worship, whether publicly or in private houses, the term ἐκκλησια is applied to them in the New Testament; and that, too, before such a congregation might be organized, by having regular office-bearers and minister appointed over them.” (Volume 1, Page 11)
“First, the separation between man and God, occasioned by sin, more especially excludes the idea that man is competent, by the aid of reason, to devise or to regulate the constitution of the Church.” (Volume 2, Page 208)