1 Tim.2:5; Heb.9:15; John 14:6; Isa.9:6,7.
XI. UNTO this office He was appointed by God from everlasting; and in respect of his manhood, from the womb called, separated, and anointed most fully and abundantly with all gifts necessary. God having without measure poured out His Spirit upon Him.
Prov.8:23; Isa.42:6, 49:15, 11:2.3.4,5. 61 :1.2 ; Luke 4:17,22; John 1:14,26, 3:34.
XII. CONCERNING His mediatorship, the Scripture holds forth Christ's call to His office; for none takes this honour upon Him, but He that is called of God as was Aaron, it being an action of God, whereby a special promise being made, He ordains His Son to this office; which promise is, that Christ should be made a sacrifice for sin; that He should see His seed, and prolong His days, and the pleasure of the Lord shall prosper in His hand; all of mere free and absolute grace towards God's elect, and without any condition foreseen in them to procure it.
Heb.5:4.5.6; Isa.53:10,11; John 3:16; Rom.8:32.
XIII. THIS office to be mediator, that is, to be prophet, priest, and king of the Church of God, is so proper to Christ, that neither in whole, or any part thereof, it cannot be transferred from Him to any other.
1 Tim.2:5; Heb.7:24; Dan.7:14; Acts 4:12; Luke 1:33; John 14:6.
Like most of the Reformed orthodoxy of its day, the London Confession used the theological formulation called the covenant of grace as its tool to explain the doctrine of Christ's work. In the century previous to this, influential theologians Caspar Olevian and Zacharias Ursinus had refined and developed a clearly covenantal theology. In the seventeenth century, other men like Johannes Coccieus, Francis Turretin, and Herman Witsius continued to hone and promote this theology. This was also taught in England by William Ames, and, of course, it became crucial to the Westminster Confession.
There is much that is true in covenant theology's explanations of Christ's work, especially Christ's representative headship of his people. However, covenant theology as a system lacks strong biblical support. Evidence in Scripture for the so-called covenant of works is virtually non-existent. The covenants of works and grace become, in this system, an all-embracing grid by which the Scriptures are interpreted. It is rather odd that all of the actual covenants in the Bible become subsumed under two inferred covenants. Covenant theology is a serious attempt to explain the unity of God's work of redemption. As such it is to be commended. However, it goes astray by allowing inferences to shape the system. It needs to be reformed biblically (pun intended).