Genesis 8:7

יצא ושוב WENT FORTH TO AND FRO — It (the raven) flew in circles round and round the Ark and did not go on its errand for it suspected that he (Noah) intended to injure its mate, just as we learn in the Agada of Chelek (Sanhedrin 108b). עד יבשת המים UNTIL THE WATERS WERE DRIED UP—The real sense of the verse is what it plainly implies (until the waters of the Flood were dried up); but the Midrashic explanation (Genesis Rabbah 33:5) is: The raven went to and fro in the world being kept in readiness for another errand during the time when the rain was withheld and the waters dried up in the days of Elijah, as it is said, (1 Kings 17:6) “And the ravens brought him bread and flesh”.

וַיְשַׁלַּ֖ח אֶת־הָֽעֹרֵ֑ב וַיֵּצֵ֤א יָצוֹא֙ וָשׁ֔וֹב עַד־יְבֹ֥שֶׁת הַמַּ֖יִם מֵעַ֥ל הָאָֽרֶץ׃

and he sent forth the raven, which went forth to and fro, until the waters were dried up from off the earth.