In John 17 Jesus prays a relatively long prayer for his disciples. Also in the same chapter he asks God for things for those who will become his future disciples. "I ask not only on behalf of these, but also on behalf of those who believe in me through their word, that they may all be one. " John 17:20,21
Jesus's prayer has long-term effect since our present brothers and sisters in Christ are included in that prayer. Our prayers can also have longevity, and our other acts of service.
The effect of Jesus's prayer will still be bearing fruit in the future. But we are expected to work with him, also praying that people may become true disciples of his, as well as praying for the strengthening of the existing disciples.
In ways John 17 is a good template for us since it shows that we should pray for our fellow Christians all over the world, and for those they will reach and their dicipleship.
John 17 records one of Jesus's longest prayers, or so it seems to me. It is a copy of his intercession. He was deeply concerned for others. It is an awesome privilege to have been prayed for by Jesus himself. Yet he has done that for us!