I have said this to you, that in me you may have peace. Jesus could read their hearts like an open book. He answered their questions before they could even speak them out. And he showed them the glory of God. We can believe in Jesus because he is himself God, the Word made flesh.
Faith is already the beginning of eternal life.
In spite of their belief, Jesus warned his disciples that their faith would be put to the test and that they would fail. Jesus spoke plainly about the tragedy of betrayal and the triumph of the cross. Jesus knew the hearts of his disciples better than they knew. He knew they would desert him in his hour of trial. Such knowledge could have easily led to bitterness and rejection.