John Winthrop's address to the Massachusetts Bay colonists in 1630 described the venture as a covenant: the settlers had bound themselves to God and to each other, and if they failed, the eyes of all people would be on them, for they would be as a city upon a hill. The phrase has since been used in American political speech to mean an example to be admired. Winthrop meant it as a warning about being watched.
The colony that followed was a congregational one, in which each church covenanted its own members and full membership required an account of a personal experience of grace given before the congregation. That standard produced its own crisis when the children of members could not supply such an account, resolved by the compromise of 1662 that allowed a partial membership.
It was not a tolerant society and did not claim to be. Roger Williams was banished for arguing that the civil magistrate had no authority over conscience, and founded Rhode Island on that principle. Anne Hutchinson was tried and expelled in 1638 for holding meetings in which she said that most of the colony's ministers preached a covenant of works. Four Quakers were hanged on Boston Common between 1659 and 1661, among them Mary Dyer, who returned after banishment knowing what would follow. Boston's ministers were also closely involved in the witchcraft trials at Salem in 1692, and one of them wrote both in support and, afterwards, in caution.