Genesis 17:15
“And God said unto Abraham, As for Sarai thy wife, thou shalt not call her name Sarai, but Sarah shall her name be.”
KJV
Read in Genesis 17Meaning
God tells Abraham that Sarai is now to be called Sarah, marking her explicit place in the promise that follows.
Read carefully
As with Abraham's renaming, this is a particular covenant act and not a universal requirement that spiritual renewal involve adopting a new personal name.
Reflection
Sarah's renaming signals that she is not incidental to the promise; the narrative now places her directly within its announced fulfillment.