Spring silkworms will not run out of silk until they die, and wax torches will not dry until they turn to ashes.
The author of this poem, Li Shangyin, did not originally intend it to praise teachers. It was only used by later generations to praise teachers for their selfless dedication, conscientiousness, self-sacrifice, and illuminating the noble sentiments of others. Compare spring silkworms and candles to teachers. There are many examples of new uses of ancient poetry.
Li Shangyin's untitled poems have gorgeous words, sophisticated use of allusions, and lofty intentions. But whether these poems are love poems, epic poems, philosophical poems, or political poems, I believe different people will have different interpretations in different moods.
Extended information
Li Shangyin's "Untitled" originally described love.
Loving you is the infinite affection of "the silkworm's threads will be exhausted only when the silkworm dies, and the tears will not dry until the wax torch turns to ashes".
The whole poem uses the word "Farewell" as the main text, describing the pain of parting and the longing after parting between a pair of lovers, and expressing the extremely sincere feelings of missing each other. Some people also say that this poem expresses the poet's political frustration and mental anguish. It has a strong sad color and expresses the depth of sorrow and sorrow.