Ruth 3:4

Mark the place. According to ch. 2:17, Ruth gleaned until evening, and did not leave for home until she had threshed and winnowed her gleanings. Toward evening Boaz’ workmen also threshed and winnowed the grain they had gleaned that day, and evening by evening the pile of winnowed grain increased in size. All probably ate supper together and then went home, but someone must remain all night to guard the increasing pile of winnowed grain against theft. Naomi knew that now, at the end of the barley harvest, Boaz himself would be on hand. There would be an unusually good evening meal, and Boaz would spend the night, probably, in a tent pitched beside what was now a large pile of winnowed grain. That night Ruth did not go home as usual, but waited unobtrusively till Boaz had had time to fall asleep in the tent. In the darkness she would not be observed.

Uncover his feet. Or, “lift up the clothes that are on his feet,” according to the LXX and the Vulgate. Boaz probably lay on a pile of straw, dressed, but with his shoes off, and his mantle spread over his body for a covering.