They attacked Israel.
Yom Kippur
Yom Kippur
Combined forces from Egypt and Syria attacked Israel with the aim of regaining territory lost to Israel in 1967. The attack took Israel by surprise. The initial attack took place on Yom Kippur (thus the name) and was specifically planned on that day since most of the country would be praying and fasting, as is traditional on Yom Kippur.
Yes.
Egypt launched a surprise attack on Israel on the Jewish Holiday of Yom Kippur in 1973, beginning the Arab-Israeli War of 1973 (also known as the Yom Kippur War, the Ramadan War, and the October War).
The Yom Kippur war was a surprised attack by Egypt and Syria against Israel. During the attack the Egyptian army crossed the line drawn at Suez canal and into the fortified Israeli territory.
It was a war that started with a surprise attack against Israel from its Arab neighbors including Egypt and Syria. The US intervened to supply arms to Israel and soviet Russia supplied arms to the Arabs.
Israel
In 1979 Israel agreed to return the Occupied Sinai Peninsula to Egypt in return for peace and recognition from Egypt.
Egypt and Syria invaded Israel in 1973. They were additionally aided by Jordanian and Iraqi Expeditionary Forces.
US supported Israel. USSR supported Egypt and Syria.