Forming the Apostles
From the Catechism of the Catholic Church, Simplified
Choosing the Twelve (551)
Jesus chose twelve apostles, shared his authority with them and "sent them out to preach the Kingdom of God and to heal" (Lk 9:2). They will always be associated with his kingdom because through them Jesus directs his Church. Jesus promised them that they would "sit on thrones judging the twelve tribes of Israel" (Lk 22:30).
Placing Peter at the Head (552-553)
After Peter proclaimed "You are the Christ, the Son of the living God" (Mt 16:16), Jesus bestowed special authority upon him: "You are Peter, and on this rock I will build my Church and the gates of Hell will not prevail against it" (16:18). Peter will always remain the unshakeable rock of the Church who strengthens his brothers (Lk 22:32).
Jesus gave Peter special authority. "I will give you the keys of the Kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth will be loosed in heaven (Mt 16:19). "To bind" and "to loose" mean authority to forgive sin, to define doctrines, and to make disciplinary decisions in the Church. Jesus entrusted this authority to the Church through the apostles (Mt 18:18) and in particular, through Peter, to whom he specifically entrusted the keys of the kingdom.
Transfigured before Them (554)
Jesus said he would suffer, "be killed and on the third day be raised" (Mt 16:21). The apostles did not understand these words. Therefore, Jesus chose Peter, James, and John to come to a high mountain, to see his face and clothes become dazzling with light. They saw Jesus speak with Moses and Elijah, and heard the Father say, "This is my Son, my Chosen; listen to him" (Lk 9:35).
Disclosing His Glory (555-556)
By this action, Jesus disclosed his divine glory and revealed his death in Jerusalem. He showed that he fulfilled the law (symbolized by Moses) and the prophets (symbolized by Elijah). "The Trinity was present: the Father as the voice; the Son in a man; the Spirit in a shining cloud" (St. Thomas Aquinas). "Your disciples saw your glory, so they would understand that your passion was voluntary" (Byzantine Transfiguration Liturgy).
Jesus' Baptism proclaimed our own Baptism. His transfiguration proclaimed our resurrection when Christ "will change our lowly body to be like his glorious body" (Phil 3:21).
Unfortunately, Peter's desire to remain on the mountain shows he still did not see the need for death before entering the kingdom (St. Augustine).
Toward Death in Jerusalem (557-558)
After that, Jesus "set his face to go to Jerusalem" (Lk 9:51) knowing that a prophet should not "perish away from Jerusalem" (Lk 13:33).
Jesus still loved Jerusalem and would gather her children "as a hen gathers her brood beneath her wings" (Mt 23:37). He even wept over Jerusalem, wishing that the city "knew the things that make for peace" (Lk 19:41-42).
Entering Jerusalem (559-560)
Jesus carefully chose the time and the details of his entrance into Jerusalem. By "riding on an ass" he fulfilled the prophecy (Zech 9:9). By his humility, he conquered the Daughter of Zion (a figure of the Church). The poor and children, like the angels at his birth, acclaim: "Blessed is he who comes in the name of the Lord."