Never judge by appearances

Never base your opinion of anything merely on what it looks like, for Appearances are deceptive and Things are seldom what they seem. For example, we must crack an egg before we can be sure that it is good or bad.

See also:

• All that glitters is not gold
• The cowl does not make the monk
• All are not thieves that dogs bark at
• Clothes do not make the man
• Fine feathers make fine birds
• The tailor makes the man