A sect and a cult are very similar in definition as I stated in the previous paragraph. The are small and offer exclusive membership, they require total commitment. They also pose opposition to the wider society. The have no professional clergy but usually have a charismatic leader or founder. In many ways a sect is the opposite of a church. They are opposites in just about every way except that, like churches, they believe they have a monopoly on the truth and that they will deny what other sects or organizations say is true. They are usually relatively small, but this small size can be justified by the fact that they have some very unique views of the truth. Goerg Simmel, one of the founders of sociology saw this small size as an asset and essential factor to the sect. It must be small as it relies largely upon the closeness of the members and their oppositional standing against the wider society. Membership to these sects is also very exclusive and they have to fully commit themselves to count as members. This provides the sect with their major way of dealing with the larger society. And that is the belief that they know the truth and non-members do not. Sects are much more likely to reject the ideas of the wider society and be hostile towards it. An example is The Amish who formed small communities in the US and reject modern technology. Members of sects are sometimes asked to give total commitment, which may even include giving up income. Usually sects are started as a protest group or as the cause of a disturbance or dissatisfaction.
The following descriptors mainly characterize a church, large membership, they are inclusive, bureaucratic, they have a professional clergy, an acceptance of a wider society, and a monopoly of the truth. Churches tend to be quite large and even get to the point that they have political power as they did in England during the fifteenth century. Churches are said to be inclusive and include members who are born into the faith and baptized. They do not however, actively choose to be members and they do not have to show how religious they are. No one tests to see whether or not they agree with what the church believes as often happens in sects. Since churches are large they tend to be mainly bureaucratic with the most power at the top. They have professionals in them such as priests, vicars, rabbis etc. These high officials must undergo a certain training to prepare them for their duty. Generally churches are very open to the wider society and support the state more than sects. Members are allowed to have free dealings with the wider society although they may ask members to behave a certain way in society. Church membership only really requires a partial membership unless you are a priest or other high member and does not require total lifelong devotion to their religious pursuits and rules. Like sects they also claim to have a monopoly on the truth.
As you can see from the example above a cult and a church are the closest, or at least they are closer in beliefs and traditions than a sect and the church. Many small sects have led to the eventual making up of a church. Take for example the Protestants, which are a very prominent religious group of churches. In the beginning there were very few people who practiced what is known today as the protestant faith. However, what started with a small group of people in the form of what we would today name as a cult has eventually led into a very large group of followers which became so large that some of it’s followers developed their own renditions of the original Protestantism and formed cults that turned into denominations such as Baptist, Lutheran, and Methodist. These all still hold to the basic elements of a church therefore cannot be called sects. Because of their total difference to a the church and the difference in even the most basic of elements you can see why it would not work for a sect to develop into a church as it would suit a cult.
As you can see while all considered forms of religion these three organizations are very different. They are all compromised of different people with different beliefs, which make them unique. However over the years we can see how the cult and the church are inexplicably linked together from example such as the formation of the Protestant faith and even Christianity as Jesus and his disciples could even have been considered a cult at the beginning.