Bob Costas is among the sporting world’s more respected reporters — and for good reason, I think. But Costas exposed a surprising ignorance during the Olympic opening ceremony when discussing Israel and the Jewish sabbath.

Here’s what he said as Isreal’s contingent entered the opening ceremony:

[Israel’s President] Shimon Peres is here. He is staying at a hotel very close to the Bird?s Nest stadium. I mention that because since this ceremony may carry over into Saturday, he can?t violate the Sabbath by being driven away from the stadium so he will have to walk it back to the hotel, which he will do post midnight tonight.

Someone should tell Costas that Judaism uses a lunar calendar. Holidays (including shabbat) start at sundown. Once the sun set in Beijing Friday night, Peres was compelled to walk back to his hotel. By midnight, the sabbath would have been well underway.