by Arthur W. Pink

In his defense of the Satisfaction of Christ, Turretin pointed out how that there are three kinds of union known to us in human relations which justifies the imputation of sin one to another; natural, as between a father and his child; moral and political, as between a king and his subjects; voluntary, as between friends, or between an arraigned criminal and his sponsor. But the union of Christ with His people rests on far stronger ground than any of these considered alone. It was voluntary on His part, for He spontaneously assumed all the obligations He bore. But it was also a covenant ordinance, decreed by the three Divine persons in counsel, whose behests are alone the foundation of all law, all rights, and of all obligations. “The Scriptures plainly teach that God has established between Christ and His people a union sui-generis, transcending all earthly analogies in its intimacy of fellowship and reciprocal co-partnership both federal and vital” (Dr. C. Hodge).

The mediatorial position assumed by Christ and the redemptive work which He performed cannot be rightly understood till they are viewed in connection with the Everlasting Covenant. It is not difficult to see that the death on the Cross was only made possible for the Son of God by His becoming Man. But we need to go farther back and ask, What was the relation between Christ and His people that made it meet for Him to become incarnate and die for them? It is not enough to say that He was their Surety, and Substitute. True, blessedly true, He wrought and suffered for them because He was their Surety to the offended Law-giver and Judge. But what rendered it proper that He should occupy such a place? No satisfactory answer can be given till we go right back to the counsels of the Godhead. Covenant oneness accounts for all, vindicates all, explains all.
Christ was substituted for His people because He was and is one with them-identified with us and we with Him; not merely as decreed by the sovereign authority of the Godhead, but as covenanted between the eternal Father and the eternal Son. Christ “bore the sins of many” because in His covenant identification with them, their sins became sinlessly but truly His sins; and unto the sons and daughters of the covenant, the Father imputes the righteousness of His Son, because, in their covenant oneness with Him, His righteousness is undeservedly but truly their own righteousness. This alone explains all Christ’s history as the incarnate Son of God; all His interposition as the Savior of His people; and it places the career of Christ on earth in its true relation to the eternal purpose of God. In its completeness, as bearing on the covenant-clients as well as the covenant-Head, it is the formal instrument by which faith comes into sure possession of Christ Himself and the benefits of redemption.

Christ is expressly denominated “the last Adam” (1 Cor. 15:45), and therefore are we told that the first Adam was “the figure of Him that was to come” (Rom. 5:14). Adam was a “figure” of Christ in quite a number of ways, but supremely in this, that he stood as the federal head of a race. God entered into a covenant with him (Hosea 6:6, margin), and therefore he stood and fell as the legal representative of all his family: when he sinned, they sinned; when he died, they died (Rom. 5:12-19). So was it with the “last Adam”: He stood as the covenant Head and federal Representative of all His people, being legally one with them, so that He assumed and discharged all their responsibilities. The birth of Christ was the begun manifestation of the eternal union between Him and His people.

In the Covenant, Christ had said to the Father, “I will declare thy name unto my brethren, in the midst of the Church will I sing praise unto thee. And again, I will put my trust in him. And again, Behold I and the children which God hath given me” (Hebrews 2:12, 13). Most blessedly is this explained in what immediately follows: “Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same,” and therefore “He is not ashamed to call them brethren.” Federation is the root of this amazing mercy, covenant – identification is the key which explains it. Christ came not to strangers, but to “brethren”; He came here not to procure a people for Himself, but to secure a people already His (Eph. 1:4; Matthew 1:21).

Since such a union has existed between Christ and His people from all eternity, it inevitably followed that, when He came to earth, He must bear their sins, and now that He has gone to heaven they must be clothed (Isa. 61:10) with all the rewardableness of His perfect obedience. This is the strongest buttress of all in the walls of Truth, yet the one which has been most frequently assailed by its enemies. Men have argued that the punishment of the Innocent as though He were guilty was an outrage upon justice. In the human realm, to punish a man for something of which he is neither responsible nor guilty, is, beyond question, unjust. But this principle did not apply to Christ, for He had voluntarily identified Himself with His people in such an intimate way that it could be said, “For both He that sanctifieth, and they who are sanctified, are all of one” (Heb. 2:11).
When we say that the union between Christ and His people is a federal one, we mean that it is of such a nature as to involve an identification of legal relations and reciprocal obligations and rights: “By the obedience of One shall many be made [legally constituted] righteous” (Rom. 5:19). God’s elect were “chosen in Christ” (Ephesians 1:4). They are “created in Christ Jesus” (Ephesians 2:10). They were circumcised in Him (Colossians 2:11). They are “made the righteousness of God in him” (2 Corinthians 5: 21). In view of this ineffable union, Scripture does not hesitate to say, “We are members of his body, of his flesh, and of his bones” (Ephesians 4:30).