fasting

"When Yom Kippur Occurs on Shabbat"

Why did the rabbis who set the Hebrew calendar allow Yom Kippur to occur on Shabbat? After all, when Yom Kippur falls on Shabbat, Jews are unable to fulfill the mitzvah of “Oneg Shabbat,” and “Oneg Shabbat” is not something that may be easily dismissed!