Mark 9:33-37 NIV
They came to Capernaum. When he was in the house, he asked them, “What were you arguing about on the road?” But they kept quiet because on the way they had argued about who was the greatest.
Sitting down, Jesus called the Twelve and said, “Anyone who wants to be first must be the very last, and the servant of all.”
He took a little child whom he placed among them. Taking the child in his arms, he said to them, “Whoever welcomes one of these little children in my name welcomes me; and whoever welcomes me does not welcome me but the one who sent me.”
NIV: New International Version