Value your parabatai,” he said. “For it is a precious bond. All love is precious. It is why we do what we do. Why do we fight demons? Why are they not fit custodians of this world? What makes us better? It is because they do not build, but destroy. They do not love, but hate only. We are human and fallible, we Shadowhunters. But if we did not have the capability to love, we could not guard humans; we must love to guard them. My parabatai, he loved like few ever could love, with all and everything. I see you are like that too; it burns more brightly in you than the fire of Heaven
Cassandra Clare, City of Heavenly Fire