The book was published in 1962, a time in Jewish history in which the magnitude of the Holocaust was beginning to surface. The book's setting during the aftermath of the Khmelnytsky massacres could be seen as a historical parallel to what many American Jews were thinking and feeling during the early 1960s.
The book contains criticism of the hypocrisy inherent in a narrow-minded interpretation of Judaism. The Jews of Pilitz in The Slave make a point of keeping commandments between man and God, but many treat Sarah and Jacob in ways that does not square well with Jewish ideals. The character of Gershon is especially cruel and often gets his way simply by bullying others, yet he keeps a strictly kosher home.
Also prominent in the story is the theme of vegetarianism. Singer himself was a passionate vegetarian and Jacob's attitude towards animals during his captivity and his explanation at the end of the novel of his vegetarian philosophy could be seen as Singer writing autobiographically.