One of the basic laws of logic is the "Law of the Excluded Middle." Plainly stated it is this: "For any proposition, either that proposition is true, or its negation is true." This is the very nature of propositions. They are either true or false. There is no other option. In today's reading from the Operation Save America Bible reading schedule Jesus uses this basic law to make a point.
Luke 9:49,50 " And John answered and said, Master, we saw one casting out devils in thy name; and we forbad him, because he followeth not with us. 50 And Jesus said unto him, Forbid him not: for he that is not against us is for us."
The apostle John has been thinking through some of the implications of what Jesus has been teaching and is apparently convicted. The apostles had seen a man casting out demons in the name of Jesus but he was not one of the twelve. They went to him and said, "Hey, you can't do that. You are not part of our denomination. And plus, you aren't licensed."
Jesus reply supplies us with a basic either or proposition. You are either "AntiChrist" or "For Christ." There is no middle ground. The proposition, "You are Antichrist," is either true or false. There isn't a third option.
This has some very important implications. First of all, notice that Jesus does not say, "He that is not for us is against us." Logically speaking, this is also true. But it is interesting to note that Jesus says, "He that is not against us is for us." Man is born into a state of depravity. We are born sinners and, "are by nature children of wrath." (Ephesians 2:3) If an individual has not positively responded to the gospel then that person is still yet, "antichrist." There is no need for that person to "sell their soul to the devil." The transaction was already made when Adam initiated war against his maker, seeking to be autonomous and independent from the giver of life.
In order for a person to become "pro-christ" he or she must surrender and submit to the conquering King. God lovingly provided for man's reconciliation by coming to pay the debt for war crimes committed. Woe to the rebel who will not lay down his arms and join the winning side.
Another interesting implication of this verse is that any institution that has the "wrong Jesus" or the "wrong gospel" is in fact antichrist. But any church that has at its core the right gospel and the right Jesus is in fact prochrist. If an individual is prochrist, he is in fact my brother even though we may have strong disagreements. This is not to say that we should get rid of denominations. We need to have loving debate over what is the true meaning of scripture. And if we are not in agreement about doctrines it is okay to separate and labor in different fields as Paul and Barnabas did in the book of Acts. But we should not say that an individual or Church is cultic lightly. If they are orthodox in essentials and are not lawless, then we should embrace them as brothers and bid them godspeed.
One final thing I would point out is that this passage contradicts the Roman Catholic teaching of "apostolic succession." The apostles are very clearly told that even though this man was not part of the twelve, he was still working the works of God in Christ's name. God's seal of approval was upon him. He had the right Jesus, the right gospel and was empowered by the right Spirit. He was one of them even though he was not commissioned with them. Christ was not going to maintain the unity of his church in history through an institution. The new Temple of God is made of men instead of stones. What makes the temple the temple is the inhabiting Spirit of God, who is the Spirit of Truth, and the Spirit of Holiness. We are unified together in him.
He that is not with me is against me: and he that gathereth not with me scattereth. - Luke 11:23
For other foundation can no man lay than that is laid, which is Jesus Christ..16 Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you? - 1 Corinthians 3:11