Explanation that the spring silkworm will not run out of silk until it dies, and the wax torch will turn to ashes before the tears dry up

In spring, silkworms don't spin out their last silk until they die, and candle tears dry up when candles burn to ashes (candle tears stop flowing, candle tears are the wax oil when the candle burns).

It is a metaphor for the dedication of mothers, teachers, etc.

Synonyms: work hard and die