冰炭不言冷热自明如人饮水冷暖自知
[bīng tàn bù yán lĕng rè zì míng rú rén yĭn shuĭ lĕng nuăn zì zhī]
Translated as 'Cold ice, hot charcoal don't speak but clearly express heat and cold; Just like when drinking water only oneself knows its warmth.' This profound statement speaks of inner experiences where one's personal feelings and knowledge cannot be understood by others.