(1.) The union that there is between the _vine_ and the _branches_, John xv. 1, 2, 5. whereby life, nourishment, growth and fruitfulness are conveyed to them: in like manner all our spiritual life together, with the exercise and increase of grace, depend on our union with, abiding in, and deriving what is necessary thereunto, from him. (2.) It is also compared to the union there is between the _head_ and _members_, as the apostle farther illustrates it, when he styles _him the head, from which all the body, by joints and bands, having nourishment ministered, and knit together, increaseth with the increase of God_, Col. ii. 19. which is a very beautiful similitude, whereby we are given to understand, that as the head is the fountain of life and motion to the whole body, as the nerves and animal spirits take their rise from thence, so that if the communication that there is between them and it, be stopped, the members would be useless, dead, and insignificant: so Christ is the fountain of spiritual life and motion, to all those who are united to him. (3.) This union is farther illustrated, by a similitude taken from that union which there is between the foundation and the building; and accordingly Christ is styled, in scripture, _the chief corner stone_, Eph. ii. 20. and a _sure foundation_, Isa. xxviii. 16. And there is something peculiar in that phrase which the apostle uses, which is more than any similitude can express; when he speaks of Christ as the _living stone_, or rock, on which the church is built; and of believers, as _lively stones_, 1 Pet. ii. 4, 5. to denote, that they are not only supported and upheld by him, as the building is by the foundation, but enabled to put forth living actions, as those whose life is derived from this union with him. (4.) There is another similitude taken from that nourishment which the body receives, by the use of food; and therefore our Saviour styles himself the _bread of life_, or the _bread which cometh down from heaven, that a man may eat thereof, and not die_; and proceeds to speak of his _giving his flesh for the life of the world_; and adds, _he that eateth my flesh and drinketh my blood, dwelleth in me, and I in him_, John vi. 48-56.