you can learn from anyone
Proverb from the Analects of Confucius meaning that in any group of people, there is always someone from whom you can learn something.
As the saying goes, 'If three walk together, I'll have a teacher,' it's important to have an attitude of learning from anyone.
Standard kanji spelling of the proverb.
Variant using Arabic numeral ３ for 三.
From the Analects of Confucius (『論語』). The original Chinese is 「三人行、必有我師焉」.