Jesus knew that the children of God were terribly divided.
O Jerusalem, Jerusalem, the city that kills the prophets and stones those who are sent to it! How often would I have gathered your children together as a hen gathers her brood under her wings, and you were not willing (Matthew 23:37)!
God’s prophets foretold the Good News of the coming Messiah, or Christ (Messiah is from the Hebrew and Christ from the Greek. Both mean the Anointed One of God who would bring salvation). When people began speculating as to who Jesus was, Jesus asked His followers a question.
“But who do you say that I am?” Simon Peter replied, “You are the Christ, the Son of the living God.” And Jesus answered him, “Blessed are you, Simon Bar-Jonah! For flesh and blood has not revealed this to you, but my Father who is in heaven. And I tell you, you are Peter, and on this rock [the rock being the truth that Jesus is the Christ] I will build my church, and the gates of hell shall not prevail against it. 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 shall be loosed in heaven” (Matthew 16:15–19).
Jesus was going to build His church. His church would be the place of safety. His church would be where His rule would be; it would be His Kingdom made up of people from every nation (Matthew 28:19) it would thus fulfill God’s promise to Abraham that all nations would be blessed through him. His apostles (chosen followers) would have special authority to deliver the prophecies from God concerning the church of Christ.
Before Jesus gave his life on the cross to pay the price for our sins, He prayed for the unity of God’s children in the coming era.
I do not ask for these only, but also for those who will believe in me through their word, that they may all be one, just as You, Father, are in me, and I in You, that they also may be in us, so that the world may believe that You have sent me. The glory that You have given me I have given to them, that they may be one even as we are one, I in them and You in me, that they may become perfectly one, so that the world may know that You sent me and loved them even as You loved me (John 17:20–23).