Even Buddha loses his temper on the third time.

Literal

Buddha [possessive-の] face [even-も] three-times.

仏の顔も三度 is a well-known proverb meaning 'even Buddha's face (loses patience after being stroked) three times.' It teaches that everyone has limits — even the most patient person will eventually get angry. The full form is 仏の顔も三度撫でれば腹を立てる.