Greetings, <class>. Crusaders like you are a welcome sight in these desolate reaches.
Your holy strength is needed to help fight the endless undead here. We need you to collect a large number of scourgestones and bring them to High Priest Thel'danis. The high priest can be found guarding Uther's Tomb in Sorrow Hill, not far from here.
Only one with an Argent Dawn Commission can hope to find scourgestones, so speak to Officer Pureheart if you haven't already.