וַיְהִ֤י הַשֶּׁ֙מֶשׁ֙ בָּ֔אָה וַעֲלָטָ֖ה הָיָ֑ה וְהִנֵּ֨ה תַנּ֤וּר עָשָׁן֙ וְלַפִּ֣יד אֵ֔שׁ אֲשֶׁ֣ר עָבַ֔ר בֵּ֖ין הַגְּזָרִ֥ים הָאֵֽלֶּה׃
И было так, что когда солнце зашло и наступила густая тьма, вот дымящаяся печь и пылающий факел, который проходил между этими кусками.
Zohar Chadash
But before the five covenants were given, there was only the covenant with fire, as it is stated (Genesis 15:17), “and behold, a smoking furnace and a flaming torch, etc.” And it is written (Genesis 15:18), “On that day the Lord made a covenant with Avram, saying.” But the fire was a covenant at first. And this is [the meaning of] Bereishit - take out fire (esh) from there, and brit (covenant) remains. Meaning to say, brit esh (a covenant of fire).