Included In Your Neighbor
How can we daven for someone to do teshuva? Are we not taught, "All is in the hand of heaven, except for the fear of heaven?" But Hashem includes all souls, and whatever is in the Whole is also in each part. Each soul therefore includes all other souls. When you yourself do teshuva, you can bring your neighbor to do teshuva. This is because you are included in your neighbor, and your neighbor is included in you.
(Rebbe Pinchas of Koretz)