Mark 9:36

And he took a little child, and set him in the midst of them: and taking him in his arms, he said unto them, Whosoever shall receive one of such little children in my name receiveth me, and whosoever receiveth me, receiveth not me, but him that sent me.

This was an acted parable teaching the same lesson which the Lord stated verbally in Matthew 18:4-6. True greatness is not a matter of position and power but in the child-like qualities of innocence, trustfulness, humility, lack of prejudice, lovableness, faith and teachableness. Receiving a little child in Jesus' name includes the unselfish care and support given for little children and also the quality of receiving an humble believer on the basis of his simple trust in the Lord, and without regard to any lack of earthly preeminence on his part.