Saint Francis of Assisi reappears throughout the novel mostly when Frank Alpine discusses him. When Frank was an orphan, the priest used to read portions of Saint Francis's book Saint Francis's Little Flowers to the boys. Frank always longed to achieve the goodness that Saint Francis embodied. The constant reappearance of Saint Francis in the text, or through the images of flowers and birds, constantly reminds Frank of his desire to be good, even though he continues to always do wrong. Saint Francis also was an eclectic monk who preached that poverty was the way to reach God and was Christ's true message. The Catholic Church of his time considered Saint Francis's ideas incorrect and dangerous, since their ability to collect funds from their parishes kept them rich. Morris Bober, however, shares Saint Francis's perspective and accepts his impoverishment as a way that he has remained spiritually afresh. Eventually, Frank Alpine will come to accept impoverishment as well and despite living in it, will be able to spiritually transform.
The idea that the grocery where the Bobers' work is a prison occurs often throughout the novel. Helen Bober always thinks of her home as a prison and once even dreams of it as such. The merchants who find Frank Alpine working in the shop warn him to leave or he will get stuck there too, in a prison-like death tomb. The idea of prison relates to Malamud's discussion of suffering and redemption. When asked about the prison motif in his work, Malamud once stated, "I use it as a metaphor for the dilemma of all men: necessity, whose bare we look through and try not to see. Social injustice, apathy, ignorance. The personal prison of entrapment in past experience, guilt, obsession—the somewhat blind or blinded self. A man has to construct, invent his freedom." Within The Assistant, the only character who does not think of the grocery as a prison is Morris Bober. Although he is not happy there, he has come to accept the grocery store and he also does not see it as the sole factor imprisoning him in his life. As Frank Alpine changes, he will willingly come to live in the prison of the grocery despite everyone's warnings. His doing so is possible because his changed self as altered the nature of his imprisonment, as his soul has been freed.
Phrases and words from the Yiddish Language dominate the way that Morris and Ida Bober speak. Malamud emphasizes their native language by placing Yiddish words directly in the text such as: "landsleit" (countrymen), "parnusseh" (livelihood), and "gesheft" (business). The use of Anglicized Yiddish terms also demonstrates their native language, such as the Polish woman being a "Poilisheh," the Italian tenant being an "Italyener," and the possible robbers being "holdupnicks." Most importantly, Malamud directly translates from the Yiddish into the English, with the parts of speech not appearing in their normal American locations. For example, Ida's inquiry of Morris, "You said to him something not nice," might normally be expressed in American English as, "You said something not nice to him?" The Yiddish phrasing helps to ground the characters' ethnic backgrounds. It also plays an important textual role in indicating Frank Alpine's evolution. Toward the end of the novel, Frank too occasionally thinks in Yiddish phrasings, indicating his full embrace of Morris Bober's philosophy.