Yet must the sons of God be still the sons of peace, and continue their prayers and endeavours for unity, how small soever be the hopes of their success: "If it be possible, as much as in us lieth, we must live peaceably with all men," Rom. xii. 18. So far must they be from being guilty of any schisms or unlawful divisions of the church, that they must make it a great part of their care and work to preserve the unity and peace of christians. In this therefore I shall next direct them. _Direct._ I. Understand first wherein the unity of christians and churches doth consist: or else you will neither know how to preserve it, nor when you violate it.[138] Christians are said to be united to Christ, when they are entered into covenant with him, and are become his disciples, his subjects, and the members of his (political) body. They are united to one another when they are united to Christ their common Head, and when they have that spirit, that faith, that love, which is communicated to every living member of the body. This union is not the making of many to be one christian, but of many christians to be one church; which is considerable either as to its internal life, or its external order and profession. In the former respect the bonds of our union are, 1. The heart covenant (or faith). 2. And the Spirit: the consent of Christ and of ourselves concurring, doth make the match or marriage between us; and the Spirit communicated from him to us is as the nerves or ligaments of the body, or rather as the spirits which pass through all. The union of the church considered visibly in its outward policy, is either that of the whole church, or of the particular churches within themselves, or of divers particular churches accidentally united. 1. The union of the whole is essential, integral, or accidental. The essential union is that relation of a head and members, which is between Christ and all the visible members of his church: the foundation of it is the mutual covenant between Christ and them, considered on their part as made externally, whether sincerely or not: this is usually done in baptism, and is the chiefest act of their profession of the faith. Thus the baptismal covenant doth constitute us members of the visible church. The integral and accidental union I pass by now. 2. Besides this union of the universal church with Christ the universal Head, there is in all particular organized churches, a subordinate union, (1.) Between the pastor and the flock. (2.) Between the people one towards another;[139] which consisteth in these their special relations to each other. 3. And there is an accidental union of many particular churches: as when they are united under one civil government; or consociated by their pastors in one synod or council. These are the several sorts of church union.