וַֽיהוָ֛ה פָּקַ֥ד אֶת־שָׂרָ֖ה כַּאֲשֶׁ֣ר אָמָ֑ר וַיַּ֧עַשׂ יְהוָ֛ה לְשָׂרָ֖ה כַּאֲשֶׁ֥ר דִּבֵּֽר׃
And the LORD remembered Sarah as He had said, and the LORD did unto Sarah as He had spoken.
Read kabbalistic (mystical) interpretation of Genesis 21:1: and classical mystical sources.