The Church, as a society, owes its origin to Christ:
it derives from Him its government and office-bearers;
it receives from Him its laws and constitution;
it draws from Him its spiritual influence and grace;
it accepts at His hand its ordinances and institutions;
it acts in His name, and is guided in its proceeding by His authority.
In the expression that the Lord Jesus Christ is the Head of the Church, and in the fact that He is the only source of Church, power, there is much more implied that that He is the founder of the Christian society. He is both its founder and its administrator,–being the ever present source of life and influence, of ordinance and blessing, or law and authority, of word and doctrine within the community. Through His Spirit, and His word, and His ordinances, alike of government and grace, Christ both originates and administers His Church upon earth.
Is it the spiritual life of the Christian Church that is inquired of in regard to its source and supply? Christ is the Head of the Church as the source of life, breathing that spiritual breath into the body at the first, and holding it in being ever since.
Is it the doctrine of the Church that is inquired after in regard to its origin and obligation? Christ is the Head of doctrine to His Church having been Himself the unerring Teacher of wisdom and truth since the beginning, and still continuing to instruct His people savingly in all Divine knowledge by His word and Spirit.
Is it the ordinances of the Church that you inquire about, in respect to their authority, and the blessing contained in them? Christ is the Head of the Church as to ordinances, having appointed them by His authority at first, and made them the channel of spiritual blessings to His people ever since.
Is it the Divine grace connected with word and ordinance that you inquire after? Christ is the Head of His Church as to grace, immediately imparting it as He wills through His appointed ordinances, or by means of His Spirit, and thereby making the Church a living and gracious power in the souls of its true members.
Is it the authority of the Church in its transactions and decisions that is inquired about; and is it asked whence has it this authority that it claims? Christ is the Head of His Church as to authority and government, speaking through its voice, and binding through its decisions, and making these His own, in so far as they are framed according to His mind and word.
In all that regards its life and doctrine, and ordinances, and grace, and authority; in short, in all that belongs to the Church as a peculiar society on earth, we recognise its Jus Divinum–the presence and the power of its Divine Head. All is derived from Him; and all emanates from Him as its source. Within the province of the Church, the Lord Jesus Christ is the only Teacher, Lawgiver, and Judge.
If doctrine is taught, it is taught because He has revealed it;
if ordinances are administered, they are administered in His name, and because they are His;
if government is established and exercised, it is through His appointment and authority;
if saving grace is dispensed, it is dispensed through the virtue and power of His Spirit;
if a blessing is communicated, it is because He blesses.
In the language of the Confession of Faith, “there is no other Head of the Church but the Lord Jesus Christ.”
(The Church of Christ: Volume Two, 194-95)
(HT: Kevin DeYoung)