You did not choose me, but I chose you and appointed you that you should go and bear fruit and that your fruit should abide, so that whatever you ask the Father in my name, he may give it to you.
Jesus told His disciples that they were chosen to go into the world with the gospel. This is sort of John's version of the Great Commission right smack dab in the middle of a passage on growing in Christ. The disciples were branches on the vine, expected to bear fruit, and were appointed by their Master to go into the world to do so.
I find it interesting then that in a sense, mission is built into the call of discipleship to grow in a maturing relationship with Jesus. It is the culmination of obeying His commands, loving one another, and remaining in Christ's love. We have to go forward with the gospel to our neighbors and the nations. We aren't growing if we aren't going!