Rashi writes that amei haaretz, ignorant people, despite the fact that they are suspected of laxity in observing the laws of taharah, ritual purity, on a Yom Tov they are not suspected of being lax, and if an am haaretz touched food on Yom Tov, it does not become tamei. We find that an am haaretz is believed on Shabbos to say that he tithed produce, as even an ignorant Jew is in awe of Shabbos.

We should utilize the Shabbos and the Yomim Tovim for Torah study, as even ignorant Jews are on a higher spiritual plane on these holy days, so certainly one who studies Torah on these holy days will be greatly uplifted.