Some children were brought to Jesus for blessing and prayer. For some reason, the disciples rebuke those bring the children. Perhaps they think Jesus is too important or too busy to mess about with such things.
Jesus had a better idea. Let them come.
The concept of children as examples of the citizens of God’s kingdom was discussed in chapter 18. Jesus is looking for people who don’t consider themselves to be of a higher status. Children have little status. They are automatically poor in spirit. Jesus what Jesus wants.
So Jesus exemplifies his command by his action. He blessed them and presumably prayed for them as well. This is a rare occasion where Jesus praying for someone is in view. Now he prays for us at the right hand of the Father.
Jesus incarnated what he taught. He, too, presented himself as of a lowly status. Humility fits him, as it should fit all Christians. The kingdom of God is a humble kingdom.