Church membership, in Christianity, is the state of belonging to a local church congregation, which in most cases, simultaneously makes one a member of a Christian denomination and the universal Christian Church. Christian theologians have taught that church membership is commanded in the Bible. The process of becoming a church member varies based on the Christian denomination. Those preparing to become full members of a church are known variously as catechumens, candidates or probationers depending on the Christian denomination and the sacramental status of the individual. Christian theologians such as Bostwick Hawley teach that church membership is commanded in scripture, grounding this in the fact that "apostolic letters are addressed to the Churches", "Apostolic salutations are to Churches", "Jesus Christ is the founder of the Church", "authority and power of discipline are vested in the Church", "Believers on earth are a part of the true spiritual Church", the "general Church is the spiritual kingdom of Christ", "Jesus Christ is Head of the Church, and Christians in an organized capacity are the body", "Ecclesia, meaning assembly...designates a Church, or congregation of Christians, having the ordinances of the Gospel and discipline duly administered", and "To the Church belong the ministry, the Scriptures, and ordinances for the perfecting of the saints". Hawley states that the duty of church membership is taught: Reformed theologian Kevin DeYoung argues that church membership keeps Christians accountable to God. Missiologist Ed Stetzer states that membership in the church exemplifies covenant theology. Those who are interested in becoming an Anabaptist Christian are known as Seekers. After a person has attended an Anabaptist church and wishes to join church membership, he or she enters a six-month proving period in which he/she "is instructed in the church beliefs and practices, which may include review of the church guidance and statements of faith, such as Dordrecht Confession of Faith (1633)".