Almost all who claim to be Christians are agreed on the need for evangelism. However, evangelicals are still distinguished by their authoritative proclamation of man's state in sin, necessitating a personal response to Christ in repentance and faith. As distinct from vaguer conceptions, evangelicals believe in the new birth of individuals. In recent years, however, the pattern in which such conversions are most frequently expected to occur has been linked with the practice of calling people to the front during an evangelistic service. This is 'the invitation system' characteristic of modern mass evangelism.