The previous verses of this chapter gave us the scene of Jesus’ twelve asking a childish question concerning who was the greatest in the Kingdom of Heaven.
Jesus knew the genesis of this question to be self-serving. He saw the immaturity of his twelve and brought a child in the midst of them to make a point about humility in the Kingdom of Heaven. Verse 4 "Whoever humbles himself like this child is the greatest in the kingdom of heaven."
Now verses 5 & 6 are words of warning from our LORD. There is an eternal consequence to receiving or harming the ‘little ones’ who come to the Kingdom in their trusting humility. There is a dire warning here. Verses 7-9 explain the woeful consequences that temptation brings … especially the temptations that misdirect the ‘little ones’