Meaning of the word "a book is a good friend when it lays bare the errors of the past" in English

What does "a book is a good friend when it lays bare the errors of the past" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

a book is a good friend when it lays bare the errors of the past

US /ə bʊk ɪz ə ɡʊd frend wen ɪt leɪz ber ði ˈer.ərz əv ðə pæst/
UK /ə bʊk ɪz ə ɡʊd frend wen ɪt leɪz beə ði ˈer.əz əv ðə pɑːst/
"a book is a good friend when it lays bare the errors of the past" picture

Phrase

a proverb suggesting that literature is valuable because it honestly reveals historical mistakes, allowing readers to learn from them

Example:
History students should remember that a book is a good friend when it lays bare the errors of the past.
We can avoid repeating tragedies because a book is a good friend when it lays bare the errors of the past.