You’ll find Sabal waiting in a truck near a tower in North Kyrat. Waiting . . . but not for you. You, he says, have one more job to do. Kill Amita.
Once you reach Amita’s mountaintop hideout (grappling up from the east works well), you’ll have the rather unpleasant job of killing her supporters. They’re all in Golden Path rags instead of Royal Guard armor, so they go down pretty swiftly, which is cold comfort.
Enter the cabin to meet Amita. For the last time.