I pray not only for them, but also for those who will believe in me through their word, so that they may all be one. It is not written literally: “for those who will believe in me through their word,” but “for the believers for their word in-inside [Greek: èis] me” (the Greek preposition èis, “towards, in direction of,” indicates both movement towards and location, “within, inhabitant, dwelling in a place”).
Those who recognize themselves in Jesus will have the strength to evangelize other people not only because they know and possess Jesus' Word and have received their mandate from him, but because they are immersed in His Word, because they inhabit, dwell, live within the Word and they lean on it and receive their strength from it. In the passports of those who follow Jesus "in His Word" could be written where the address should be.
Jesus' Word can be announced only from within the Word itself, more for residency than for mandate. There is a cosmic difference between knowing/possessing the Word and dwelling in it, just as there is an immense difference between reading the notes of a piece of music and being completely immersed in an orchestra which is translating those notes into vibrations creating music. One cannot announce the Word from oneself alone, but only if attached from within to the Word itself. But there is more.
Just as it is true that it is possible to announce the Gospel only from within the Gospel itself, it is also true that the announcement of Jesus' procedures must lead to unity, union and sharing in those who are listening to it. If the Gospel is not leading to unity among people, among hearts, then it is not God's way and it will lead nowhere. Jesus prays intensely that the highest good of unity be an integral part of his followers' lives because he knows that nothing has meaning or has reason to exist if, in the wonderous diversity of God's gifts, those who believe in the Son are unable to bear fruits of unity and sharing.