A prime minister's belly is big enough to pole a boat in — meaning a great man is tolerant.
Tips
history
宰相 is a general term for the highest-ranking official who assisted the emperor in running the government. The exact title varied by dynasty (丞相, 相国, 中书令, 内阁首辅 etc.). Ming emperor Hongwu abolished the post in 1380.
usage
In modern contexts 宰相 refers only to historical figures. The modern term for prime minister is 总理 (PRC) or 首相 (Japan, UK).