The tablets weren’t the only things that were smashed beyond repair when Moses came down from that mountain and saw the Israelites and the Golden Calf. Something had changed, deep down at Moses’ core, which we don’t really read about until we get to the end of the parasha, Ki Tisa.
In the beginning of the parasha, we get some of the last instructions about the building of the Mishkan, the Tabernacle, specifically, the wash basin and laver that Aaron and the other Priests were to use in purifying themselves. Then we read about the Sabbath, and how important it was to the people and to God. Twice we read that Shabbat is a “sign”, something tangible between God and the people, for all times.
Then comes the Calf. Moses is up on the mountain, the people get restless, and get Aaron to build for them a god to go before them. Moses comes down with the first set of tablets, sees the rowdy partying at the base of the mountain, around the Calf, and smashes the tablets to the ground. Then, he has to go back up to God, and get a new set of tablets. It is on this second trip we see the “sign” on Moses’ face, “So Moses came down from Mount Sinai…bearing the two tablets…Moses was not aware that the skin of his face was radiant, since he had been talking with God.” (Ex 34:29) The people shrank from him, but Moses called them back, and he told them all that he had learned on Mount Sinai this second time. After that, when he was finished speaking, Moses put a veil over his face. From then on, whenever Moses went in to speak with God, he left the veil off, but when he was finished, he covered his face again, when telling the people what God had said.
Perhaps it wasn’t the time up on the mountain that changed Moses and his face, it was the encounter with the people and the Calf. Moses saw the level of betrayal the people were capable of, and perhaps he needed to veil himself from seeing it anymore. Moses went from the height of spiritual experience talking to God, to the depths of human behavior. The experience showed on his face, and after having witnessed the Calf, he needed to make a barrier between himself and the people. Maybe it was so he could hold on to his experience. Maybe it was so it wouldn’t get sullied by the people who had acted so badly.
Moses’ veil may have kept the people away from the strange countenance, but it also allowed Moses to keep his time with God close to himself. From that moment on, the veil was a “sign” too. If Shabbat was a sign between God and the people, the veil could have been a sign between Moses and God, for all the people to see.