1. As Christ is constituted by the Father the Savior of those that believe, who, being exalted. in heaven to the right hand of the Father, communicates to believers all those blessings which he has solicited from the Father, and which he has obtained by his obedience and pleading, but as the participation of blessings cannot be through communication, unless where there has previously been an orderly and suitable union between him who communicates and those to whom such communications are made, it is, therefore, necessary for us to treat, in the first place, upon the union of Christ with us, on account of its being the primary and immediate effect of that faith by which men believe in him as the only Savior.
2. The truth of this thing, and the necessity of this union, are intimated by the names with which Christ is signally distinguished in a certain relation to believers. Such are the appellations of head, spouse, foundation, vine, and others of a similar kind; from which, on the other hand, believers are called members in his body, which is the entire church of believers, the spouse of Christ, lively stones built on him, and young shoots or branches. By these epithets, is signified the closest and most intimate union between Christ and believers.
3. We may define or describe it to be that spiritual and most strict and therefore mystically essential conjunction, by which believers, being immediately connected, by God the Father and Jesus Christ through the Spirit of Christ and of God, with Christ himself, and through Christ with God, become one with him and with the Father, and are made partakers of all his blessings, to their own salvation and the glory of Christ and of God.
4. The author of this union is not only God the Father, who has constituted his Son the head of the church, endued him with the Spirit without measure, and unites believers to his Son; but also Christ, who communicates to believers that Spirit whom he obtained from the Father, that, cleaving to him by faith, they may be one Spirit. The administrators are prophets, apostles and other dispensers of the mysteries of God, who lay Christ as the foundation, and bring his spouse to him.
5. The parties to be united are,
(1.) Christ, whom God the Father has constituted the head, the spouse, the foundation, the vine, etc, and to whom he has given all perfection, with a plenary power and command to communicate it;
(2.) And sinful man, and therefore destitute of the glory of God, yet a believer, and owning Christ for his Savior.
6. The bond of union must be considered both on the part of believers, and on the part of God and Christ.
(1.) On the part of believers, it is faith in Christ and God, by which Christ is given to dwell in our hearts.
(2.) On the part of God and Christ, it is the Spirit of both, who flows from Christ as the constituted head, into believers, that he may unite them to him as members.
7. The form of union is a compacting and joining together, which is orderly, harmonious, and in every part agreeing with itself by joints fitly supplied, according to the measure of the gifts of Christ. This conjunction receives various appellations, according to the various similitudes which we have already adduced. With respect to a foundation and a house built upon it, it is a being built up into [a spiritual house]. With respect to a husband and wife, it is a participation of flesh and bones; or, it is flesh of the flesh of Christ, and bone of his bones. With respect to a vine and its branches, or to an olive tree and its boughs, it is an engrafting and implanting.
8. The proximate and immediate end is the communion of the parts united among themselves; this, also, is an effect consequent upon that union, but actively understood, as it flows from Christ, and positively, as it flows into believers, and is received by them. The cause of this is, that the relation is that of disquiparency, where the foundation is Christ, who possesses all things, and stands in need of nothing; the term, or boundary, is the believer in want of all things. The remote end is the external salvation of believers, and the glory of God and Christ.
9. But not only does Christ communicate his blessings to the believers, who are united to him, but he likewise considers, on account of this most intimate and close union, that the good things bestowed, and the evils inflicted on believers, are also done to himself. Hence, arise commiseration for his children, and certain succor, but anger against those who afflict, which abides upon them unless they repent, and beneficence towards those who have given even a draught of cold water, in the name of Christ, to one of his followers.