In modern Reformed churches, membership in a particular local church is ordinarily taken for granted as Biblical, historical, and obligatory. However, while some aspects of church membership may be permissible and good, it is a relatively modern practice to require the making of a membership covenant, and one rooted in Independent and Congregationalist ecclesiology.
The swearing of an oath as part of a membership covenant is permissible, but that oath cannot be obligatory for joining a church. The sacraments are also not to be denied to those who do not agree to the membership covenant, as the Biblical requirements for membership in the visible church and participation in the sacraments are a profession of faith, and living a life free of scandal.
Any such oath is also limited by God's Word; those who agree to a membership covenant may not promise to do something which may lead them into sin. Any membership covenant which grants the elders or other church members the right to constrain the new member to sin is forbidden. This means that the membership covenant cannot require members to stay members at that particular congregation unless released by that church.
§ Samuel Rutherford
John Cotton wrote a treatise
Question 1: Whether the Seals of the Covenant can be denied to professors of approved piety, because they are not members of a particular visible Church, in the New Testament.
Our Brethren deny any Church Communion, and the seals of the Covenant, Baptism, to the children of Believers, the Lord's Supper to believers themselves, who come to them from Old England, because they be not members of the particular Congregation to which they come, and because there is no visible Church in the New Testament, but one particular Parish, and all who are without a particular Parish, are without the visible Church, and so are not capable of either Church censures, or the Seals of the Covenant, because none have right to the seals of the Covenant, but only this visible Church.
We hold all who profess faith in Christ, to be members of the visible Church, though they be not members of a visible Congregation, and that the seals of the Covenant should not be denied to them.
We hold that those who are not members of a particular Congregation, may lawfully be admitted to the seals of the Covenant.
First: Because those to whom the promises are made, and profess the Covenant, these should be baptized. But men of approved piety are such, though they be not members of a particular Parish. The proposition is Peter's argument, Acts 2:38.
Secondly: Those who are not Members of a particular Church may be visible professors, and so members of a visible Church, Ergo, the seals of the Covenant belong to them.
Thirdly: The contrary opinion has no warrant in God's Word.
Fourthly: The Apostles required no more of those whom they baptized, but profession of belief, as Acts 10:47: "Can any forbid water that these should not be baptized, who have received the Holy Ghost, as well as we?" Acts 8:37: "If thou believest with all thy heart, thou mayest he baptized": no more is sought of the Jailor, Acts 16:31-34.
Rutherford also addresses the idea of a church covenant, by which the Congregationalists formed their churches. In it, they required new members to agree to the covenant.
Proposition 3: All are entered by covenant into a Church-state, or into a membership of a visible Church.
Answer: Here are we to encounter with a matter much pressed by our reverend Brethren, called a Church covenant. A Treatise came unto my hand in a Manuscript of this Subject; In their Apology, and in their answer to the questions propounded by the Brethren of Old England this is much pressed.
The Congregationalists required the following four conditions to be met before allowing a person to become a member:
A public vocal declaration of the manner and soundness of their conversion, and that either in continued speech or in answer to questions propounded by the elders.
A public profession of their faith, concerning the articles of their religion, in the same manner.
An express vocal covenanting by oath, to walk in that faith; and to submit themselves to God, and one to another, in his fear; and to walk in a professed subjection to all his holy ordinances, cleaving one to another, as fellow members of the same body in brotherly love and holy watchfulness unto mutual edification in Christ Jesus.
A covenanting, not to depart from the said church, without the consent thereof.
An explicit vocal Covenant whereby we bind our selves to the first three Articles in a tacit way, by entering in a new relation to such a Pastor, and to such a Flock, we deny not, as if the thing were unlawfull, for we may swear to perform God's commandments, observing all things requisite in a lawful oath. But that such a covenant is required by divine institution, as the essential form of a Church and Church-membership, as though without this none were entered members of the visible Churches of the Apostles, nor can now be entered in Church-state, nor can have right unto the seals of the covenant, we utterly deny.
Any professor moving from one congregation to another, and so comming under a new relation to such a Church, or such a Ministry, is in a tacit and virtual covenant to discharge himself in all the duties of a member of that Congregation, but this is nothing for a Church-covenant; for when six are converted in the congregation whereof I am a member, or an excommunicated person heartily and unfainly repents, there arises a new relation between those converts and the Church of God; and a tie and obligation of duties to those persons greater then was before, as being now members of one mystical and invisible body. Yet our brethren cannot say, there is requisite, that the Church renew their Church-covenant towards such, seeing the use of the Covenant renewed is to restore a fallen Church, or to make a non-Church to be a Church; and if those six be converted by my knowledge, there results thence an obligation of a virtual and tacit covenant between them and me; but there is no need of an explicit and vocal covenant, to tie us to duties that we are now obliged to in a stricter manner then we were before; for when one is taken to be a steward in a great family, there may be a sort of Covenant between that servant and the Lord of the house, and there results from his office and charge a tie and obligation, not only to the head of the family, but also to the children and fellow-servants of the house; but there is no need of an express, vocal, and professed covenant between the new steward and the children and servants; yes and strangers also, to whom he owes some acts of steward-duties, though there results a virtual covenant. Far less is there a necessity of an express and vocal covenant before that steward can have claim to the keys, or be received in office. So when one enters into covenant with God, and by faith lays hold on the covenant, there results from that act of taking the Lord to be his God, a covenant-obligation to do duty to all men, as the covenant of God does oblige him; yes, and to do works of mercy to his beast (for a good man will have mercy on the life of his beast) and he is obliged to a duty by that covenant with God to his children, which are not yet born, to servants who are not yet his servants, but shall hereafter be his servants, to these who are not yet converted to Christ, now it is true a virtual and tacit covenant, results toward all these, even toward the beast, the children not yet born, &c. when the person first by faith enters in covenant with God; but none, master of common sense and judgement will say there is required a vocal and explicit, and professed covenant, between such an one entered in covenant with God, and his beast, and his children not yet born, or that the foresaid tacit and virtual covenant, which does but result from the man his covenanting with God is either the cause, or essence, or formal reason, whereby he is made a formal contracter and covenanter with God. So, though when I enter a member of such a congregation, there arises thence an obligation of duty, or a tacit covenant, tying me in duties to all members present, or which shall be members of that congregation, though they should come from India; yet in reason it cannot be said, that there is required an express vocal covenant between me and all, who shall be fellow-members of this congregation; and far less that such a covenant does make me a member of that congregation, yes, because I am already a member of that congregation; thence arises a tacit covenant toward such and such duties and persons.
Then the question is not if there be a tacit and virtual covenant when persons become members of such a visible congregation. Nor do we question whether such a Church-covenant may be lawfully sworn. We think it may, though to swear the last article not to move from such a congregation without their consent, I think not lawful, nor is my habitation in such a place a matter of Church-discipline.
§ Moving Congregation
Rutherford here argues that there are events that occur which require people to move congregation, such as a lawful calling (a vocation, or job). If someone's job required them to travel overseas, then the Congregationalist fourth vow would prevent them from leaving without breaking the vow. Yet their vocation and its requirements are lawful and not of sin! The person moving congregation has not committed any sin, yet they would keep him at that congregation unjustly.
Now if any be to travel by sea, and to travel to far countries in a lawful calling, he is legally unclean and incapable of the seals to himself or his seed; for he cannot in conscience and through necessity of his lawful calling swear your church oath, for he must swear to observe the manners of his fellow-members, to edify them by exhortation, consolation, rebuking, to join himself in an external covenant to that visible church, yea never to remove thence, except the congregation consent. So your oath obliges him to all these, now this is impossible because of his lawful calling, and because he cannot be a church-member for ever. While he travels in his lawful calling, the comfort of the Lord's Supper is denied to him, and baptism to all his seed, and that by a strong hand of providence without any fault in him. Show us a warrant from the Law and the Testimony, where any are to be debarred from the seals of the covenant, and that ordinarily, (where sickness and some other physical impediments do not occur) where there is no moral unworthiness or guiltiness in the persons debarred. Will you debar all from church comforts, the presence of Christ in his Church, the comfort of his walking, beside the candlesticks, and his influence in the word preached, the power of the keys, the rebukes of the saints, their exhortation and private comforting of sinners, the comforts of the ordinances of baptism and the Supper of the Lord, because a strong hand of providence in a lawful calling does perpetually debar them? You say your trying of church members is a means blessed of God, to try many men's sincerity. I answer, unlawful means, as the persecution of tyrants, may have this success, what then? Is it a lawful means? I would God's name here were spared; it is not a means blessed of God, it chases away many from the net of the gospel, and the pastoral care of the shepherds, and is not a conquering way to gain souls.
Next, we see that Ruthford addresses the idea of separating compared to removing. The Congregationalists said that masters of families should separate them all from the churches of England, because some of them were profaning the Supper through popish ceremonies.
I see not how all these arguments, taken from moral commandments, do not oblige son as well as father, servant as master, all are Christ's free men, son or servant, so as they are to obey what ever Christ commands, Matthew 18:10 and with the spouse to seek Christ in the fullest measure, and in all his ordinances, and son and servant are to know their own heart, so as they have need of all Christ's ordinances; and are no more to remain in a congregation where their souls are famished, because fathers and masters neglect to remove to other congregations, where their souls may be fed in the fullest measure; then the Apostles in Acts 4:29 and 5:29 were to preach no more in the Name of Jesus, because the rulers commanded them to preach no more in his Name. And therefore, with reverence of our godly brethren, I think this distinction of persons free, and sui juris, and of sons and servants, not to be allowed in this point.
It is one thing to remove from one congregation to another, and another thing to separate from it, as from a false constitute Church, and to renounce all communion therewith, as if it were a synagogue of Satan and Antichrist, as the Separatists do, who refuse to hear any minister ordained by a prelate.
An apparent contradition shows up later in the book, as Rutherford addresses leaving a less clean church to join a more clean church.
There is no just cause to leave a less clean church (if it be a true church) and to go to a purer and cleaner, though one who is a member of no church, have liberty of election, to join to that church, which he conceives to be purest and cleanest.
How could this be, given that Rutherford has been explaining just causes to leave churches? A vocation, or job, which requires someone to leave one church and attend another in a distant country is a just cause to leave one church and go to another.
We see that Rutherford uses the word "leave" to mean not merely removing from one congregation to another, but a separation alike to that being pursued by the Congregationalists, and explained in the previous section.
Luther had authority against him, and the powers of the World, it was one point of Reformation that John the Baptist took up, against the law of the land to preach against Herod's sin; for if popery be in a land, to leave popery is a great degree of Reformation.
It is admirable that leaving a parishional church in England, they leave not the true visible church, so all the parishional churches in England must be separated from, as from no churches
Even just before Rutherford mentions leaving a less pure church to join a purer church, he says this
There is a forced separation through tyranny from personal communion, and a voluntary separation; David was forced to leave Israel, and was cast out of the inheritance of the Lord; the former is not our sin, and our separation from Rome has something of the former, the latter would be wisely considered.
The entire section in which it is found in is addressing separation from churches, rather than merely moving from one congregation to another. In Rutherford's understanding, it is legitimate to separate from or leave a false church and join a true church. It is not legitimate to separate from or leave a true but impure church for the sole reason of joining another true and purer church. An example of a legitimate separation or leaving would be to leave the Roman Catholic church to join a Reformed church. An illegitimate separation or leaving would be to leave the Lutheran church to join a Reformed church, for the sole reason of seeking greater purity. The Lutheran church is a true church, if less pure, and not to be separated from.
Note again that separation, or leaving is not the same as merely moving/removing. It is to renounce all communion therewith, as if it were a synagogue of Satan and Antichrist.
We conclude that Rutherford did not permit church leaders to have the authority to prevent members from moving from one congregation to anothers. He also forbade members from swearing such an oath as to prevent them from moving congregation without permission. He was strongly against the idea of separating from true churches, but allowed freedom to move from one congregation to another.