John 17:20-21

Jesus looked up to heaven and said, “Father, I ask not only on behalf of these, but also on behalf of those who will believe in me through their word, that they may all be one. As you, Father, are in me and I am in you, may they also be in us, so that the world may believe that you have sent me.”

Jesus’ second prayer at the last supper is for future generations of believers, including ourselves. His prayer is that all of us will be united with God our Father and with him. He is to share with all of us what is deepest in his heart – the glory he had from the beginning of time. Love wants to share all that is best with the beloved.

Further commentary available here