פָּנִ֣ים ׀ בְּפָנִ֗ים דִּבֶּ֨ר יְהוָ֧ה עִמָּכֶ֛ם בָּהָ֖ר מִתּ֥וֹךְ הָאֵֽשׁ׃
C’est face à face que l’Éternel vous parla sur la montagne, du milieu de la flamme.
Rashi on Deuteronomy
פנים בפנים FACE TO FACE — R. Berechia said: Thus did Moses, in effect, say: Do not think that I am misleading you with something which does not exist at all, as an agent does acting between the vendor and the purchaser; behold, the seller Himself is speaking to you (God who transmitted the Torah to you) (cf. Pesikta Rabbati 21: Pesachim Rabbah פ' י' הדברות קמייתא).
Sforno on Deuteronomy
פנים בפנים, not in a nocturnal vision when you were asleep.