'Sarah,' as a mother, represents divine truth. She also denotes truth joined to good and divine truth. 'Sarah,' as a wife, in Genesis 18:6, signifies rational truth pertaining to the Lord. As a sister, she denotes the rational principle. Sarai was called 'Sarah' so she would represent the divine intellectual principle by adding the 'H' from the name of Jehovah. 'Thou shalt not call her name Sarai, but Sarah shall her name be,' signifies that the Lord shall put off His humanity, and put on the divinity.

(Reference: Arcana Coelestia 1468)