The answer is: Sarai

Genesis 17:15 - God changed Sarai's name to Sarah when He reaffirmed His covenant with Abraham, signifying her new role as the mother of nations.

Sarai, which means "my princess" in Hebrew, had a significant name change that carried weighty implications. When God transformed her name to Sarah, meaning "princess," it came loaded with purpose. It wasn’t just a title; it marked her pivotal role as the matriarch of nations, linking her to a grand legacy shown through the later generations, including kings among her descendants.

It's interesting to note how often names in the Bible signify a transformation or a mission. For example, Jacob was renamed Israel after wrestling with God, capturing the essence of struggle and triumph—a beautiful metaphor for the nature of faith itself. Similarly, this change for Sarah wasn’t just decorative; it symbolized divine favor and a covenant promise that stretched across the ages.

Let's take a moment to appreciate the incredible journey Sarah went through. She was well into her nineties when she bore Isaac, reflecting deep faith in the face of impossible odds. The New Testament gives a nod to this historical account in Hebrews 11:11, showcasing Sarah's faith, as she accepted God's promise against all human reasoning—an impeccable lesson in hope and resilience.

Her name change marked the beginning of something extraordinarily fruitful, echoing throughout biblical narrative to present times, emphasizing how faith, even in skepticism, can pave paths toward miraculous outcomes. Isn’t it magnificent how these stories intertwine, allowing us to grasp deeper meanings behind the seemingly simple changes in name and narrative?