Jamieson, Fausset & Brown, on Exod 34:29

“And when Moses came down from the mount Sinai, he held the two tables of the testimony, and he knew not that his face was horned from the conversation of the Lord.”

“Moses wist not that the skin of his face shone while he talked with him--It was an intimation of the exalted presence into which he had been admitted and of the glory he had witnessed (Co2 3:18); and in that view, it was a badge of his high office as the ambassador of God. No testimonial needed to be produced. He bore his credentials on his very face; and whether this extraordinary effulgence was a permanent or merely temporary distinction, it cannot be doubted that this reflected glory was given him as an honor before all the people.”

Imported from an open dataset — not yet checked against the printed edition.