What Does Genesis 21:3 Mean?

Abraham gave the name Isaac to the son Sarah bore him. The naming of the child is obedience to the divine specification of chapter 17:19 where God said "you are to call him Isaac." The patriarch uses the name God gave, aligning his household's identity with the divine description. The name Isaac (Yitzhak, "he laughs") carries the memory of Abraham's incredulous laughter in chapter 17 and Sarah's disbelieving laughter in chapter 18, now transformed.

Every time the name "Isaac" is spoken, the history of the laughter of doubt is invoked. The son whose name means "he laughs" will make his mother say in verse 6, "God has brought me laughter." The laughter that was disbelief becomes laughter of fulfilled joy through the faithfulness of the God who promised. The scandal of impossibility is permanently embedded in the covenant heir's name as a witness to the divine capacity to do what seems absurd.

God named the child; Abraham used the name God gave. The covenant is organized through divine naming: Abram became Abraham (chapter 17), Sarai became Sarah (chapter 17), and now the heir receives the name God specified. Jesus's name, given by divine instruction to Mary (Luke 1:31) and Joseph (Matthew 1:21), follows the same pattern. The covenant's key person receives the divine-specified name through the obedient act of those responsible for naming him.