Covenant is like marriage. It is a real bondage with promises, responsibilities and curses. God works with his creation by covenant. Covenant is God’s initiation and we respond to this by faith.
In OT we read that God made the Covenant with Israel, from the time of Christ’s ascension and Pentecostal we have inauguration of NC. Covenant is something real and visible. We can count members of Covenant because of sign of initiation in NC which is baptism. All baptized persons in Christian Church are members of the New Covenant.
The Bible teaches us that the bondage of husband and wife is also Covenant. We have ceremony of inauguration of this (wedding), blessings, promises, responsibilities and curses. Husband is the Covenant Head of his family. By this he represents Christ as the head of His family (The Church). So Husband is responsible for his wife and children. Of course the man could be faithful and lovely husband – then he and his family are under God’s blessings. Or he can be unfaithful, covenant-breaking husband. Then he is under curse. If there was no divorce, husband is still husband. If there was no excommunication, the member of the Church is still a member of the Covenant. His obligation as husband makes his sin more terrible. He is under God’s curse. The same situation is when we look at the members of the NC. They objectively are in covenantal relationship with God. They are Christians. But their hypocrisy, unfaithfulness, are reasons why they are under bigger judgment than people outside the Covenant (Hbr 6:4-6, Hbr 10:29).