As Stanley walks back to his hole, he worries what Mr. Sir will do to him when he recovers. He also realizes that, because of the time spent at the Warden's cabin, he'll be digging long after the others have finished.
Now he starts to think about his great-grandfather, who was robbed by Kissin' Kate Barlow. Kissin' Kate left Stanley's great-grandfather alone in the desert, where he somehow managed to survive for seventeen days before he was rescued. He told his rescuers that he survived because he "found refuge on God's thumb" (21.7).
In his pensive haze, Stanley nearly steps on a rattlesnake on his way back to the holes. In case things weren't scary enough already.
When he gets back to the place where the boys are digging, he finds that his hole is almost finished. Huh? Thinking that the other boys dug the hole to thank him for taking the blame for stealing the sunflower seeds, he smiles and thanks them. But none of the other boys takes credit for digging his hole.
At that moment, Stanley notices that Zero's hole is barely begun: it was Zero who dug the hole for him. Well how about that?