The words schism and schismatic have found their heaviest usage in the history of Christianity, to denote splits within a church or religious body. In this context, "schismatic", as a noun, denotes a person who creates or incites schism in a church or is a member of a splinter Church and, as an adjective, refers to ideas and activities that are thought to lead to or to constitute schism, and so departure from what the user of the word considers to be the true Christian Church. These words have been used to denote both the phenomenon of Christian group splintering in general, and certain significant historical splits in particular.
Some religious groups make a distinction between heresy and schism. Heresy is rejection of a doctrine that a Church considered to be essential. Schism is a rejection of communion with the authorities of a Church, and this term has historically been applied to such a break when there was no dispute about doctrine.
The First Council of Nicaea distinguished between the two. It declared Arian and non-Trinitarian teachings to be heretical and excluded their adherents from the Church. It also addressed the schism between Peter of Alexandria and Meletius of Lycopolis, considering their quarrel to be about a matter of discipline, not of faith.
The divisions that came to a head at the Councils of Ephesus and Chalcedon were seen as matters of heresy, not merely of schism. Thus, the Eastern Orthodox Church and Oriental Orthodoxy consider each other to be heretical, not orthodox, because of the Oriental Orthodox Church's rejection and the Eastern Orthodox Church's acceptance of the Confession of Chalcedon about the two natures, human and divine, of Christ.
An individual who withdraws from communion with the authorities of a Church, but who is neither expelled from it nor formally breaks with it, remains a member, though a disobedient one. On the other hand, when it is a group and not just individuals who withdraw from communion, two distinct ecclesiastical entities result. Often, each of the two then accuses the other of heresy.
In Roman Catholic Church canon law, an act of schism, like an act of apostasy or heresy, automatically brings on the individual concerned the penalty of excommunication. As stated in canon 1312 §1 1° of the Code of Canon Law, this penalty is intended to be medicinal, so as to lead to restoration of unity.
The Nicene Creed declares belief in the One Holy Catholic and Apostolic Church. Those who accept this creed therefore generally believe they should be united in a single Church or group of Churches in communion with each other. The ancient Churches consider that they represent the One Holy Catholic and Apostolic Church: for instance, the Roman Catholic Church claims that title and considers the Eastern Orthodox Church to be in schism, while the Eastern Orthodox Church also claims that title and holds that the Catholic Church is schismatic and probably heretical; some Protestant Churches believe that they also represent the One Holy Catholic and Apostolic Church and consider the Orthodox and Catholic Churches to be in error, whilst others have in effect abandoned any expectation of a wholly united Church. See also Great Apostasy.
It has been recently suggested that the Roman Catholic Church in Poland might be heading for a schism. The potential breakaway church led by Father Rydzyk was named "The Rydzyk Church of Poland" , an ironic expression, or the "Toruń-Catholic Church" (in Polish: kościół toruńsko-katolicki). In Poland the latter term is sometimes used to refer to the ideology of Father Rydzyk and his followers who are known as the Radio Maryja Family.
However, the central text of Islam, the Qur'an ordains that Muslims are not to be divided into divisions or sects and rather be united under a common goal of faith in one God alone - Allah, failure to do which has also been deemed a sin by God and thus forbidden.
According to a Hadith (collections of accounts of the life and teachings of Muhammed) report, Muhammed is said to have prophecised "My Ummah (Community or Nation) will be fragmented into seventy-three sects, and all of them will be in the Hell fire except one." The Sahaba (his companions) asked him which group that would be, whereupon he replied, "It is the one to which I and my companions belong" (reported in Sunan al-Tirmidhi Hadith No. 171).
The Qur'an also ordains that the followers of Islam need to 'obey Allah and obey the Messenger (i.e. Prophet Muhammed)' stressing on the importance of keeping the commandments mentioned in the Qur'an by Allah, and following all the teachings of Muhammed,; labeling everyone who concurs as a 'Muslim' and a part of the 'best of communities brought forth from mankind'.
The word Sunni comes from the word Sunnah, which means the teachings and actions or examples of the Islamic prophet, Muhammad. Therefore, the term Sunni refers to those who follow or maintain the Sunnah of Muhammad.
The Sunni believe that Muhammad died without appointing a successor to lead the Muslim ummah (community). After an initial period of confusion, a group of his most prominent companions gathered and elected Abu Bakr, Muhammad's close friend and father-in-law, as the first Caliph. Sunnis regard the first four caliphs, Abu Bakr, Umar (`Umar ibn al-Khattāb), Uthman Ibn Affan and Ali (Ali ibn Abu Talib) as the al-Khulafā’ur-Rāshidūn or "Rashidun" (The Rightly Guided Caliphs).
Sunnis believe that the position of Caliph may be democratically chosen, but after the first four Rightly Guided Caliphs the position turned into a hereditary dynastic rule. After the fall of the Ottoman Empire in 1923, there has never been another widely recognized Caliph.
Shia Islam is the second largest denomination of Islam. Shi`a Muslims believe that, similar to the appointment of prophets, Imams after Muhammad are also chosen by God. According to Shi`as, Ali was chosen by Allah and thus appointed by Muhammad to be the direct successor and leader of the Muslim community. They regard him as the first Shia Imam, which continued as a hereditary position through Fatimah and Ali's descendants.
Not strictly a denomination, Sufism is a mystical-ascetic form of Islam practised by both shia and Sunni Muslims. By focusing on the more spiritual aspects of religion, Sufis strive to obtain direct experience of God by making use of "intuitive and emotional faculties" that one must be trained to use. Sufism is usually considered to be complementary to orthodox Islam, although Sufism has been criticized by many Muslims for being an unjustified Bid‘ah or religious innovation. One starts with sharia (Islamic law), the exoteric or mundane practice of Islam and then is initiated into the mystical (esoteric path of a Tariqah (Sufi Order). Sufi followers consider themselves as Sunni or Shia , while there are a few others who consider themselves as just 'Sufi' or Sufi-influenced.
Kharijite (lit. "those who seceded") is a general term embracing a variety of Islamic sects which, while originally supporting the Caliphate of Ali, eventually rejected his legitimacy after he negotiated with Mu'awiya during the 7th Century Islamic civil war (First Fitna). Their complaint was that the Imam must be spiritually pure, and that Ali's compromise with Mu'awiya was a compromise of his spiritual purity, and therefore of his legitimacy as Imam or Caliph. While there are few remaining Kharijite or Kharijite-related groups, the term is sometimes used to denote Muslims who refuse to compromise with those with whom they disagree.