This sentence comes from Heine's The Trouble of Youth. The poems in this book are the works of Heine's youth, deeply influenced by German folk songs and the poems of romantic poets similar to folk songs, with pure and simple style; The language is concise and lively; The rhythm is rigorous and beautiful; There are various forms, including majestic short poems, long poems, group poems, and well-formed sonnets.
Extended data
The enlightenment of this sentence:
This is a sign of maturity. At a certain age, the mind is no longer impetuous, and everything is hidden in the heart, not expressed in emotion. Even if you can't see one more thing, you don't immediately show your attitude, but you have an evaluation in your heart. This kind of practice makes people see things more comprehensively, do things more calmly and make themselves more mature.
Hate what you like and stay away from the people you love. Growth is a lonely journey. People who hate it will only use everything they care about relentlessly and repeatedly, and their duty is to protect everything they care about. Because you have to understand that no matter how big the world is, there will always be people you don't like.