An allusion is an indirect reference to a person, event, or text outside of the narrative itself, often without explanation, which allows authors to layer meaning and history from outside sources onto their own writing in a compressed form. Biblical allusions permeate Jacob Have I Loved, much in the same way that Methodism structures life on Rass Island. Some of this presence comes through direct quotation, such as the title itself, the reading from the Psalms during the hurricane, and Grandma’s gleeful recitation of Romans 9:13 when only Louise can hear it.

The Bible also structures Louise’s understanding of her life. In Chapter 6, she concludes that is “a murderer. Like Cain” (75) because she hates her sister. This is an allusion to the story of Cain's murder of his brother Abel in Genesis 4, a particularly extreme instance of sibling rivalry. Scriptural passages come into her mind unbidden, as when she goes to find the Captain during the storm:

And everyone that heareth these sayings of mine and doeth them not, shall be likened unto a foolish man, which built his house upon the sand: and the rain descended and the floods came, and the winds blew, and beat upon that house (119).