“The church exists primarily for two closely correlated purposes: to worship God and to work for his kingdom in the world ... The church also exists for a third purpose, which serves the other two: to encourage one another, to build one another up in faith, to pray with and for one another, to learn from one another and teach one another, and to set one another examples to follow, challenges to take up, and urgent tasks to perform. This is all part of what is known loosely as fellowship.”