Who is the greatest?/Sermon while holding a child

Mark 9:33b and being in the house he asked them, What was it that ye disputed among yourselves by the way? 34 But they held their peace: for by the way they had disputed among themselves, who should be the greatest. Matt 18:1 At the same time came the disciples unto Jesus, saying, Who is the greatest in the kingdom of heaven? Luke 9:46 Then there arose a reasoning among them, which of them should be greatest.

Mark 9:35 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 [1].

Mark 9:36a And he took a child, and set him in the midst of them:and when he had taken him in his arms,

Matt 18:2 And Jesus called a little child unto him, and set him in the midst of them, Luke 9:47 And Jesus, perceiving the thought of their heart, took a child, and set him by him,
Mark 9:36b he said unto them, Matt 18:3a And said, Luke 9:48a And said unto them,

Matt 18:3b Verily I say unto you, Except ye be converted, and become as little children, ye shall not enter into the kingdom of heaven. 4 Whosoever therefore shall humble himself as this little child, the same is greatest in the kingdom of heaven.

Mark 9:37 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. Matt 18:5 And whoso shall receive one such little child in my name receiveth me. Luke 9:48b Whosoever shall receive this child in my name receiveth me: and whosoever shall receive me receiveth him that sent me: for he that is least among you all, the same shall be great.
Mark 9:38 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. Luke 9:49 And John answered and said, Master, we saw one casting out devils in thy name; and we forbad him, because he followeth not with us.
Mark 9:39 But Jesus said, Forbid him not: for there is no man which shall do a miracle in my name, that can lightly speak evil of me. 40 For he that is not against us is on our part. Luke 9:50 And Jesus said unto him, Forbid him not: for he that is not against us is for us [2].
       

Mark 9:41 For whosoever shall give you a cup of water to drink in my name, because ye belong to Christ, verily I say unto you, he shall not lose his reward.

[1]The indication that the last shall be first and the first, last is also found in Mark 9:35, 10:31, Matthew 19:30, 20:16, and Luke 13:30.

[2]This is explicitly contradicted by Luke 11:23 .