What is the meaning of this quote? How does it relate to Singer?"Literature is the memory of humanity."
Isaac Bashevis Singer, the winner of the 1978 Nobel Prize for literature, wrote his novels and stories in Yiddish, the language of Eastern European Jews. Many of his stories are set in the mileau of Eastern European Jewish communities, a world that was destroyed by the Holocaust. The Yiddish language was--to a large extent--"destroyed" along with the communities that spoke it.
(Yiddish certainly lives on. I myself can speak it and read it. Still, it is the living, spoken language only in a few, relatively small enclaves in America, Western Europe, and Israel. The vast majority of Jews today speak, write, think, and dream either in the vernacular of their country, or in Hebrew, which is the language of the modern State of Israel.)
Through his literature, Singer kept alive the memory of Eastern European Jewry, or at least his perception of it. When Singer received the Nobel Prize, Lars Gyllenstein of the Swedish Academy commented:
the Middle Ages seem to spring to life again [in Singer's works]; the daily round is interwoven with wonders, reality is spun from dreams, the blood of the past pulsates in the present.