The Brethren are believers in the Lord Jesus Christ who earnestly desire to follow New Testament principles of life, fellowship, worship, ministry, and mission. They do this without forming any official denomination or control, accomplishing their goals through voluntary cooperation. They recognize that they are not the only Christians who desire or profess to follow the New Testament in certain doctrines or patterns, but more importantly, in principles and goals.

The most notable of these is their determination to make worship and the remembrance of the Lord Jesus Christ in the Lord's Supper primary. Along with this is their principle that this worship should actively involve all believers. Not only priesthood, but in ministry, is the privilege and responsibility of Christians; and this without need of ordination or a prescribed sequence of preparation.

The Brethren movement arose in 1826 at a time when denomination barriers were strong, when most of the church's ministry was restricted to the clergy, and before the various cooperative movements and councils familiar to us now had come into being. Several groups had come into existence in such widely diverse places as the U.S., Great Britain, and Switzerland that met in simple fellowship, and worship. Some continued, others did not, but the one in Dublin become known as the forerunner of the movement. One member of this group was Anthony Norris Groves. He is known for today for his warm openness to believers of all nominational persuasions. Another, who joined the group shortly after it began, was John Nelson Darby. A prolific writer (he also translated the Bible into English, German, and the New testament in Italian), Darby expressed some of the convictions of the early brethren in strongly worded pamphlets.

One of these pamphlets offered the opinion that for ordained ministers to arrogate the leading of worship and of the Lord's Supper only to themselves denied the reality of the Spirit's leading and empowering of all Christians in many other groups have increasingly recognized the diversity of the Spirit's gifts to all believers.

Another conviction of the early Irish & British Brethren was that the State Church System was unbiblical. Parishioners paid pew rents, which money went both to support ministers who were in effect employees of the government, and also to support military operations (an offense to many early Brethren pacifists). The Brethren believed then and now that Christians should give voluntarily, and that those who minister should trust God alone for their support.

Today, Brethren meet weekly for the Lord's Supper, at which believers may freely express worship and praise without stated leadership. They usually call their meetings "Assemblies", to avoid using the word "Church" with its diverse meanings of denomination and building. They differ widely from one another in many ways, but still seek to maintain their original principles. For example, while many groups now have full-time "resident workers", who may include frequent preaching among their ministries, the Brethren still cherish the principle of diversity of spiritual gifts and ministries.

And, in spite of attempts to give them a denomination name they still prefer to be known simply as "brethren".