Mark 9:33 (KJV)

And when he was come into the house, his disciples asked him privately, Why could not we cast him out?

And he said unto them, This kind can come forth by nothing, but by prayer and fasting.

And they departed thence, and passed through Galilee; and he would not that any man should know it.

For he taught his disciples, and said unto them, The Son of man is delivered into the hands of men, and they shall kill him; and after that he is killed, he shall rise the third day.

But they understood not that saying, and were afraid to ask him.

But they held their peace: for by the way they had disputed among themselves, who should be the greatest.

And he sat down, and called the twelve, and saith unto them, If any man desire to be first, the same shall be last of all, and servant of all.

And he took a child, and set him in the midst of them: and when he had taken him in his arms, he said unto them,

Whosoever shall receive one of such children in my name, receiveth me: and whosoever shall receive me, receiveth not me, but him that sent me.

And John answered him, saying, Master, we saw one casting out devils in thy name, and he followeth not us: and we forbad him, because he followeth not us.