Many of Jesus' disciples found his teaching to be hard and could not accept it. Jesus tells them that there is life in his words. There is true power in what he says, but there are many who will not believe. It is not because his teaching is lacking in anything. He knows even from the beginning which of them are true followers and which ones will betray him.
Then he tells them that nobody can even come to him unless the father first makes it possible. When they heard this many of them left. They could no longer follow him.
Jesus turns to the twelve and asks them if they are going to leave as well. But, Peter replies saying basically where else are we going to go? Why would we leave? You are the holy one of God, and you have the words of eternal life. Then Jesus tells them that even though he has chosen them, he has allowed a betrayer to be part of their company. A devil is in their midst.
Nothing is a surprise to Jesus. All is going according to plan. He is in control. His word is truth. There is life in his teaching. Yet, for some reason, according to this plan, there are many who will not be enabled by the Father to come to Jesus. Some, like Judas, will even be used by God to betray his people. Peter rightly recognizes that there is no other place to go. There is no other name given under heaven by which we must be saved.
Lord, Father, draw your people to yourself through your Son that they may believe and be saved.