Commentaire sur Le Deutéronome 5:4

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).

פנים בפנים, not in a nocturnal vision when you were asleep.

The seller himself, etc. This is the meaning of, “Face to face.”

V. 4. פנים בפנים scheint eine noch größere Unmittelbarkeit auszudrücken, als das gewöhnlichere אל פנים (Bereschit 32, 30; Schmot 33, 11 und Dewarim 34, 10). Das Angesicht ist nicht nur einander zugewandt, sondern es dringt in das andere ein, vermittelst des Angesichts verkehrt das Innere des einen mit dem Innern des andern. So auch עין בעי. Bamidbar 14, 14).

פנים בפנים דבר ה' עמכם, “The Lord spoke with you face to face;” Moses refers to the first two commandments that G-d addressed directly to all the people, before they asked Moses to become their gobetween as they found G-d’s voice too overpowering and were afraid of dying. (Compare verse 22)