Some churches ask their members to sign a covenant.  A covenant is what we would use to describe the vows between a husband and his wife, and between God and his people.  Signing a covenant helps prospective members understand what it means to be a part of the church. The member covenant is not a legal document or some sort of cultic rite.  It is an affirmation, an agreement, and a source of accountability for both the church and its individual members.  Here is a sample of a membership covenant used by Redlands CRC.

Source:  Redlands Christian Reformed Church