Of Excommunication and Other Censures
The censures of the church, are appointed by Christ, for the preventing and removing, and healing of offences in the church:
for the reclaiming and gaining of offending brethren; for the deterring others from the like offenses; for purging out the leaven which may infect the whole lump; for vindicating the honour of Christ, and of his Church, and the holy profession of the gospel; and for preventing the wrath of God, that may justly fall upon the church, if they should suffer his covenant, and the seals thereof, to be profaned by notorious and obstinate offenders.
–The Cambridge Platform, 1648
From The Reformation of the Church by Iain H. Murray