yàn​què​yān​zhī​hóng​gǔ​zhī​zhì

how can small people understand the ambitions of the great

燕雀焉知鸿鹄之志 燕雀焉知鴻鵠之志 yàn​què​yān​zhī​hóng​gǔ​zhī​zhì
how can small people understand the ambitions of the great
Literally "how can a sparrow know the will of a great swan"; used to mean that common people cannot possibly understand the lofty goals or ambitions of a great person.