Midrasz do Rut 3:14

“She lay at his feet until the morning, and she arose before one could discern another, as he said: Let it not be known that the woman came to the threshing floor” (Ruth 3:14).
“She lay at his feet until the morning.” Rabbi Berekhya said: “Before [beterem] one could discern” — beterom [with a vav] is written, teaching that she stayed there six hours, corresponding to the numerical value of vav. “He said: Let it not be known that the woman came to the threshing floor.” To whom did he say it? Rabbi Meir said: To a member of his household. Rabbi Ḥunya and Rabbi Yirmeya said in the name of Rabbi Shmuel bar Rav Yitzḥak: Throughout that night, Boaz was flat on his face, and was saying: ‘Master of the universe, it is revealed and known before You that I did not touch her. Likewise, may it be Your will that it not become known that a woman came to the threshing floor, and the name of Heaven will not be profaned because of me.’