人不可貌相，海水不可斗量

rénbùkěmàoxiàng,hǎishuǐbùkědǒuliáng
you can't judge a person by appearance, just as you can't measure the sea with a pint pot (idiom)

CEDICT

Entry Composition

1 人不可貌相 rénbùkěmàoxiàng
  1. you can't judge a person by appearance (idiom)
  2. you can't judge a book by its cover
  3. often in combination 人不可貌相，海水不可斗量 rénbùkěmàoxiàng,hǎishuǐbùkědǒuliáng
2 海水不可斗量 hǎishuǐbùkědǒuliáng see 人不可貌相，海水不可斗量 rénbùkěmàoxiàng,hǎishuǐbùkědǒuliáng