"If any one would be first, he must be last of all and servant of all."

Mark 9:33-41

At that time, Jesus and his disciples came to Capernaum, and when he
was in the house he asked them, "What were you discussing on the
way?" But they were silent; for on the way they had discussed with one
another who was the greatest. And he sat down and called the twelve; and
he said to them, "If any one would be first, he must be last of all
and servant of all." And he took a child, and put him in the midst
of them; and taking him in his arms, he said to them, "Whoever
receives one such child in my name receives me; and whoever receives me,
receives not me but him who sent me." John said to him, "Teacher, we saw
a man casting out demons in your name, and we forbade him, because
he was not following us." But Jesus said, "Do not forbid him; for
no one who does a mighty work in my name will be able soon after to
speak evil of me. For he that is not against us is for us. For truly,
I say to you, whoever gives you a cup of water to drink because you
bear the name of Christ, will by no means lose his reward."