The first time ( Mk 8:31) Jesus told the apostles about His Passion, Peter wished, that it would not happen to Jesus. Jesus scolded Peter. This is the second time (Mk 9:31) Jesus predicted His suffering, death and resurrection. Learning from the last time, this time the apostles changed their tactics. Instead of making their thoughts known to the Master, they 'privately' argued amongst themselves. The text said, the apostles didn't understand what Jesus said, and were afraid to ask Him. Frightened, in Mark, associated with a weak faith in Jesus.
Like all of us, the apostles had no trouble understanding the teaching about suffering and death, but of the second part of the teaching, which says, 'He will rise again', they struggled to make sense. When a matter is tough to handle, we prefer to talk about petty issues, and lose track of the main subject. This was exactly what happened to the apostles. Instead of talking about 'what rise again' meant, the apostles were discussing which of them was the greatest.
Their 'secret' discussion did not go without the Master's knowledge. Jesus challenged them, not because of their arguing, but because of the content of the argument. Their personal ambition contradicted His teaching. Jesus took this opportunity to correct them. He told them, that humble service is the way of life, and His true disciples must love one another.
'If anyone wants to be first, he must make himself last of all and servant of all' Mk 9,35.
Jesus reminded the apostles that: First, the earthly way of government belonged to this world. It would not fit in God's kingdom. It would be obsolete in God's kingdom. For Jesus, worldly power and honour were in the state of flux, slow to come, and quick to go. Providing loving service was true power and honour. They would last forever, because people treasured them in their hearts. They carried with them wherever they go. Worldly power can crush our body, but not our spirit.
Second, greatness was to be found, not from the strong, but the weak. It was to be found not in receiving, but in giving loving service to the needy, voiceless and marginalised members of a society. To visualize His teaching, Jesus set a child before the apostles. He taught them to welcome children.
Today children are greatly protected, and hold dear in our society. At the time of Jesus, children of the poor had no social status. Jesus gave a social status to children, because they, too, were God's creation, and bored God' image and likeness. Those who do not embrace children with tender love and compassion, they are not true Jesus' disciples.
Second, when one welcomes a child, that person welcomes no one else, but part of oneself, because the childhood in each one of us does not vanish, but gives way to adulthood. We, from time to time, do behave like children.
Third, our faith depends on God's love and grace, likes a child depends on his/her parents for life and livelihood.
Fourth, by nature, children are innocent. Their state of life was not tainted by sin. A baby is seen as an angel. God's image in them was, and is much brighter. Jesus told His apostles to welcome a child, not in an ordinary way, but in His Name.
Finally, caring for a child is an act of kindness. An act of kindness moves the heart of a person. It is gained through loving and caring. Acts of kindness have deep meanings when they are done to make God's love real for others.