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.

Direct. II. Understand also wherein the communion of christians and churches doth consist; that you may know what it is that you must hold to. In the universal church your internal communion with Christ consisteth in his communication of his Spirit and grace, his word and mercies unto you; and in your returns of love, and thanks, and obedience unto him; and in your seeking to him, depending on him, and receivings from him: your internal communion with the church or saints, consisteth in mutual love, and other consequent affections, and in praying for and doing good to one another as yourselves, according to your abilities and opportunities. Your external communion with Christ and with most of the church in heaven and earth, is not mutually visible and local; for it is but a small number comparatively that we ever see; but it consisteth in Christ's visible communication of his word, his officers, and his ordinances and mercies unto you, and in your visible learning and reception of them, and obedience to him, and expressions of your love and gratitude towards him. Your external communion with the universal church, consisteth in the prayers of the church for you, and your prayers for the church; in your holding the same faith, and professing to love and worship the same God, and Saviour, and Sanctifier, in the same holy ordinances, in order to the same eternal end.

Your external communion in the same particular congregations, consisteth in your assembling together to hear the preaching of God's word, and to receive the sacrament of the body and blood of Christ, and pray and praise God, and to help each other in knowledge and holiness, and walk together in the fear of the Lord.

Your communion with other neighbour churches, lieth in praying for and counselling each other, and keeping such correspondencies as shall be found necessary to maintain that love, and peace, and holiness which all are bound to seek, according to your abilities and opportunities.

Note here, that communion is one thing, and subjection is another. It is not your subjection to other churches that is required to your communion with them. The churches that Paul wrote to at Rome, Corinth, Galatia, Ephesus, Philippi, &c. had communion together according to their capacities in that distance; but they were not subject one to another, any otherwise than as all are commanded to be subject to each other in humility, 1 Pet. v. 5. The church of Rome now accuseth all the christians in the world of separating from their communion, unless they will take them for their rulers, and obey them as the mistress church: but Paul speaketh not one syllable to any of the churches of any such thing, as their obedience to the church of Rome. To your own pastors you owe subjection statedly as well as communion; and to other pastors of the churches of Christ (fixed or unfixed) you owe a temporary subjection so far as you are called to make use of them (as sick persons do to another physician, when the physician of the hospital is out of the way): but one church is not the ruler of another, or any one of all the rest, by any appointment of the King of the church.

Direct. III. By the help of what is already said, you are next distinctly to understand how far you are bound to union or communion with any other church or person, and what distance, separation, or division is a sin, and what is not: that so you may neither causelessly trouble yourselves with scruples, nor trouble the church by sinful schism.

What unity is among all christians.

I. There must be a union among all churches and christians in these particulars. 1. They have all but one God. 2. And one Head and Saviour, Jesus Christ. 3. And one Sanctifier, the Holy Ghost. 4. And one ultimate end and hope, even the fruition of God in heaven. 5. And one gospel to teach them the knowledge of Christ, and contain the promise of their salvation. 6. And one kind of faith that is wrought hereby. 7. And one and the same covenant (of which baptism is the seal) in which they are engaged to God. 8. And the same instrumental founders of our faith, under Jesus Christ, even the prophets and apostles. 9. And all members of the same universal body. 10. And all have the same new nature and holy disposition, and the same holy affections, in loving God and holiness, and hating sin. 11. They all own, as to the essential parts, the same law of God, as the rule of their faith and life, even the sacred canonical Scriptures. 12. Every member hath a love to the whole, and to each other, especially to the more excellent and useful members; and an inclination to holy communion with each other. 13. They have all a propensity to the same holy means and employment, as prayer, learning the word of God, and doing good to others.[140] All these things the true living members of the church have in sincerity, and the rest have in profession.

What diversity will be in the church.