Anyone Not Against Us Is For Us9:49 John answered, “Master, we saw someone casting out demons in your name, and we tried to stop him, because he does not follow with us.” 50 But Jesus said to him, “Do not stop him, for the one who is not against you is for you.”
Jesus sends out the twelve in the beginning of Luke 9. He endows them with supernatural powers of the Spirit to cast out demons and to cure diseases (Luke 9:1). They now, upon their return (most likely many days after due to all the events that occurred post their return 9:10-48), tell Christ of a man they rebuked. They apparently saw him during this time in-between, apparently this gift to remove spirits was not present in this era and was exclusively a power belonging to Christ prior to his sending his twelve out. Certainly if this fringe Christian had this ability prior this time, those closest to Christ would have this ability without Christ having to bestow it upon them. This fellow undoubtedly must have witnessed the Apostles perform a casting out of a demon and sought to imitate them. This was most likely out of a desire to aid Christ’s kingdom and not for his own glory, for Christ says he is "for Him". (The apostle Paul also speaks of people who perform religious acts in the name of Christ, but he does not say they are necessarily for him, but that they are doing a thing that aids Christ’s kingdom, Philippians 1:15-18. Even the devil unwittingly aids God's kingdom yet we would never assume his is "for Christ" because of it.)
Let's look closer at verse 50 . . .
There's much that can be said about this verse, but let us focus on the topic at hand, which is total depravity. "the one who is not against you is for you". A definitive statement that can be said in reverse: no one who if for you is against you. It's pretty much stating the obvious. "My disciples, isn't it clear that if he is not against you he is for you? Why are you rebuking him, therefore?" We can deduce from this that there is no way you can be "not against" Christ and at the same time not "for Christ". THERE IS NO NEUTRAL GROUND. Many arminians assume that the natural man is not too hostile to God. They are not spiritually dead, but sick. Their lip-service to total depravity is a contradiction. If total depravity falls short of causing a man to be spiritually dead it is totally lacking. The natural men are at enmity with God (Col. 1:21).
We mind as well cover all possible scenarios
Can you be against "against Christ" and "for Christ", obviously not (though we have already discussed how we can be God's enemies and yet still in God's wisdom and in man's foolishness still work to advance the kingdom of God. In a very practical sense). Can a man be "against Christ" and "not for Christ", of course, and this is the only other option. Christ says if he is for you he is for Christ and is a believer, if not, then he is lost and against you.