Mark 9:38-43 (ESV)
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."  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.  For the one who is not against us is for us.  For 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.  "Whoever causes one of these little ones who believe in me to sin, it would be better for him if a great millstone were hung around his neck and he were thrown into the sea.  And if your hand causes you to sin, cut it off. It is better for you to enter life crippled than with two hands to go to hell, to the unquenchable fire.
This is a rather curious passage. One because you always hear people using this to justify the existence of all sorts of other churches whose doctrines conflict with what Jesus taught. “But they are doing it in the name of Jesus…” whatever. But this quickly turns into a warning against those who are most apt to use this verse, the Baptists. I say this because they are constantly teaching the little one’s who Jesus says here believe in him, not to believe in him. Of course, they would deny this. But it’s true. To believe in Jesus is to believe him. And to believe Jesus is to believe what he says concerning baptism through those whom he appointed to be his apostles. Things like, “Baptism now saves you.” But no Baptists are constantly teaching the little ones that they don’t believe in Jesus until they reach some mystical age of accountability. In teaching this they teach the little one’s to despise the gifts Jesus has given us. The little one’s believe. They ought to be baptized and nurtured in that faith.