Genesis 15:15

וַיֹּאמֶר לְאַבְרָם יָדֹעַ תֵּדַע כִּי־גֵר יִהְיֶה זַרְעֲךָ בְּאֶרֶץ לֹא לָהֶם וַעֲבָדוּם וְעִנּוּ אֹתָם אַרְבַּע מֵאוֹת שָׁנָֽה

And He said unto Abram: ‘Know of a surety that thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them four hundred years;

וְגַם אֶת־הַגּוֹי אֲשֶׁר יַעֲבֹדוּ דָּן אָנֹכִי וְאַחֲרֵי־כֵן יֵצְאוּ בִּרְכֻשׁ גָּדֽוֹל

and also that nation, whom they shall serve, will I judge; and afterward shall they come out with great substance.

וְדוֹר רְבִיעִי יָשׁוּבוּ הֵנָּה כִּי לֹא־שָׁלֵם עֲוֺן הָאֱמֹרִי עַד־הֵֽנָּה

And in the fourth generation they shall come back hither; for the iniquity of the Amorite is not yet full.’

וַיְהִי הַשֶּׁמֶשׁ בָּאָה וַעֲלָטָה הָיָה וְהִנֵּה תַנּוּר עָשָׁן וְלַפִּיד אֵשׁ אֲשֶׁר עָבַר בֵּין הַגְּזָרִים הָאֵֽלֶּה

And it came to pass, that, when the sun went down, and there was thick darkness, behold a smoking furnace, and a flaming torch that passed between these pieces.