He was in Jordan when he learned it as a kid from his Syrian neighbor, who has a proverb or saying for every single occasion. She would say this when she did not expect someone to do something right, but they do it right.
Original Script: ضربة الاعمى صيب
Transliteration: Darbet el ama saib
Literal Translation: The hit of the blind on target
Smooth Translation: The hit of the blind is on target
Although I found the saying strange, it made sense after hearing the explanation; the probability of the person doing it right is like the probability of a blind person hitting a target. Because of its similarity to the English saying “Beginner’s luck,” this saying may be used to prevent someone from thinking too highly of themself. Since Arabic cultures are past-oriented,* this saying could be used to make sure that respect for elders who consistently do that task well is not lost.
*Alan Dundes talks about past-oriented and future-oriented cultures in his “Thinking Ahead: A Folkloristic Reflection of the Future Orientation in American Worldview.”Dundes, Alan. “Thinking Ahead: A Folkloristic Reflection of the Future Orientation in American Worldview.” Anthropological Quarterly 42, no. 2 (April 1969): 53–72. https://doi.org/ 10.2307/3316639.