Marriage isn't a contract. Contracts are broken when one or more parties fails to keep its promise. Scripture compares a covenant to the ties between a parent and a child. Isaiah 49:15-16 reads:
Can a woman forget her sucking child, that she should not have compassion on the son of her womb? yea, they may forget, yet will I not forget thee. Behold, I have graven thee upon the palms of my hands; thy walls are continually before me.
Parents are committed unconditionally to their children, even when children misbehave. In a marriage covenant, vows are exchanged "for better or worse." In a contract, if one side doesn't follow through the obligation ends -- not in marriage, because marriage is a covenant.
Scripture compares church membership to the marriage covenant. I'm writing this because I don't think most people think that way about the church. Joining a church is not like joining a gym or a golf club. Ephesians 5:23 says, "For the husband is the head of the wife, even as Christ is the head of the church." In Ephesians 5, you read how Christ sees that covenant from His end. Verses 25 through 27 read:
Christ also loved the church, and gave himself for it; That he might sanctify and cleanse it with the washing of water by the word, That he might present it to himself a glorious church, not having spot, or wrinkle, or any such thing; but that it should be holy and without blemish.
The covenant into which Christ entered results in His giving Himself and sanctifying and cleansing for the good of His bride. Jesus isn't in it for Himself. He's in it for us. As the bride, we've entered into that covenant freely and voluntarily. I'm sure that people don't often get what that means and don't see it as the same.
As you've read this so far, I'm guessing that some of you have a hard time with this idea, that is, that your church membership is like a marriage covenant. When you read the New Testament epistles, that's how it reads. This is why love of the brethren is such a big deal in 1 John. It's why Jesus commands His disciples to love one another in John 15.
The marriage covenant changes the identity of two people. There are now one flesh. Everything they see, they now see through the perspective of the other. In a church covenant, a member looks at His life through His church. Covenantal commitment is the norm through all of scripture. There is an in and an out to it. You are either in or you are out. Noah and his family were in and everyone else was out. In 1 John 2:19, John writes:
They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
This is obviously church membership. When someone takes off, it just proves that he was never there in the first place.
When people take off from a church, they are not taking their covenant seriously. They are not looking at the church like Jesus describes it (her). It's very common today, that people decide they are going to go, and then they expect the church to approve. They are treating their relationship to the church as something worse than a contractual relationship, but closer to a contract than a covenant. I say closer to a contract, because when the church isn't everything they want it to be, they think they are permitted to leave the contract. Those terms are set by them and they can stay or leave however they want. Scripture takes this covenant way more seriously.
I say that people take it less serious than a contract, because the people very often do not obligate themselves almost at all. They don't see there being that kind of authority in a church. I think that most people treat their credit card contracts more serious than they do church membership, which is a stronger relationship, because the one in and with the church is a covenant. People don't take the church seriously, like Jesus takes it, because they are not taking Jesus Himself seriously. They don't take what He says seriously. They are very superficial in their relationship to the church and much more serious about other temporal and less meaningful relationships. This shows their disrespect to the church and the church covenant. This also reflects on their salvation as seen in 1 John 2:19 above.
In Matthew 18:18 talks about church membership like being bound and church discipline as being loosed. It's very serious. Someone loosed by a church is someone not regarded as saved. It's like the person was never a member in the first place. He's not viewed any longer in the covenant community.
The church possesses the ordinances, baptism and the Lord's Supper. Christ gave those to the church. Neither of these save someone, but they do show the strength of this covenant. Someone doesn't get baptized unless he is saved. He gets baptized to say he is saved. In so doing, he joins the church. The Lord's Table is communion with the Lord's body, as pictured by the elements. At the point of communion, everything is to be aligned with Jesus Christ and His body.
Baptism and the Lord's Supper are not just rituals. They are symbolic of the covenant that someone has. They have entered into the church and are continuing in the church, in its communion. Baptism and the Lord's Supper are signs of the covenant. Baptism is a sign of a death of the old life and a new life. At His Table, when Jesus said, "This is my body," He wasn't saying it was literally His body, but symbolically, His body as a sign. These are both signs of this covenant that we have. They are not the covenant, but they symbolize the covenant. Baptism brings someone into the church and the Lord's Table keeps someone in communion in and with it.
The covenant is so serious that when someone takes of the symbol unworthily, he is guilty of the body of Christ, and he could die because of it. That's what Paul writes in 1 Corinthians 11. People should take church membership seriously. Leaving a church should not be an easy thing to do.