גַּ֣ם מֵע֧וֹף הַשָּׁמַ֛יִם שִׁבְעָ֥ה שִׁבְעָ֖ה זָכָ֣ר וּנְקֵבָ֑ה לְחַיּ֥וֹת זֶ֖רַע עַל־פְּנֵ֥י כָל־הָאָֽרֶץ׃
of the fowl also of the air, seven and seven, male and female; to keep seed alive upon the face of all the earth.
Read kabbalistic (mystical) interpretation of Genesis 7:3: and classical mystical sources.