וְלִמְשֹׁל֙ בַּיּ֣וֹם וּבַלַּ֔יְלָה וּֽלֲהַבְדִּ֔יל בֵּ֥ין הָא֖וֹר וּבֵ֣ין הַחֹ֑שֶׁךְ וַיַּ֥רְא אֱלֹהִ֖ים כִּי־טֽוֹב׃
and to rule over the day and over the night, and to divide the light from the darkness; and God saw that it was good.
Read kabbalistic (mystical) interpretation of Genesis 1:18: and classical mystical sources.