וַיַּפֵּל֩ יְהוָ֨ה אֱלֹהִ֧ים ׀ תַּרְדֵּמָ֛ה עַל־הָאָדָ֖ם וַיִּישָׁ֑ן וַיִּקַּ֗ח אַחַת֙ מִצַּלְעֹתָ֔יו וַיִּסְגֹּ֥ר בָּשָׂ֖ר תַּחְתֶּֽנָּה׃
And the LORD God caused a deep sleep to fall upon the man, and he slept; and He took one of his ribs, and closed up the place with flesh instead thereof.
Read Jewish philosophical commentary on Genesis 2:21: and classical philosophical sources.