On Yom Kippur as well as repentance we should think of the Yom Kippur War of 1973, when Israel came closest to being destroyed. The Israel Defense Ministry has released archives that reveal the drama of that time, including the incredible intelligence blunder of the Head of Military Intelligence Maj-Gen. Eli Zeira, who completely ignored signs of an impending Egyptian attack, and the fears of Defense Minister Moshe Dayan that “Israel will not be able to defend itself.” Zeira and the Head of the Southern Command Maj-Gen. Shmuel Gonen were relieved of their commands.
Gen. Ariel Sharon was called back from retirement and given command of an Armored Division under Gen. Bar-Lev, who did not trust him. He was ordered not to attack but to await further orders, but he ignored that and immediately attacked the Egyptian forces and cut a way through towards the southern end of the Suez Canal, where with incredible foresight in 1967 he had built a ramp from which to construct a bridge over to the Egyptian side of the Canal. He had a mobile bridge following in the wake of his tank attack. Unfortunately they blundered into an Egyptian armored division waiting in reserve and at the battle of the Chinese Farm defeated them. They went on against incredible difficulties (and against orders) to bring up the bridge and construct the crossing and he raced his tanks over to the other side and not only destroyed the Egyptian missile defenses against the IDF, but also prevented all supplies getting to the main Egyptian Army. He had encircled the Egyptian 3rd Army and in effect he had won the war. So his daring insubordination paid off.
More Israelis died in that war (ca. 3,000) due to the lack of foresight of the Generals and the intelligence echelon than in any other war. But, despite it being on Yom Kippur and the element of surprise, Israel scored a stunning victory that paved the way for the Israel-Egyptian Peace Treaty of 1979. The Israeli Defense Ministry learned several hard lessons from this war, that in effect made the IDF even more capable than before.