What does it mean to be, "For us"?

Mark 9:38 John said to him, "Teacher, we saw someone casting out demons in your name, and we tried to stop him, because he was not following us." 39 But Jesus said, "Do not stop him, for no one who does a mighty work in my name will be able soon afterward to speak evil of me. 40 For the one who is not against us is for us. 41For truly, I say to you, whoever gives you a cup of water to drink because you belong to Christ will by no means lose his reward.

When Jesus says, "For the one who is not against us is for us," what does He mean? It is my very presumptive guess that many Christians would say, "those who believe in God and those who don't." Or, "those who go to church and those who don't." Or worse yet, "those who go to MY church and those who don't."

But Jesus does not say, "If someone gives you a cup of water because you believe in God he will not lose his reward." He says, "BECAUSE YOU BELONG TO ME!!!!!"

As Christians we need to make it clear that we belong to JESUS! Jesus is the Truth, and most people are afraid of the Truth because the Truth exposes their earthly weaknesses. People will always be more cautious of committing to the Truth than they will committing to a lie because that is the sinful nature. If we stand for anything other than JESUS people will always come willingly, but if we procliam His name then they have a serious decision to make.

When we make the very bold distinction that all people are either "for us" or "against us" we had better make very well certain exactly what it is we are for. Therefore, we ought to pray continuously for the strength to proclaim the name of Jesus, and that God reminds us of the life we have IN CHRIST ALONE.