On October 6th, 1973, the Yom Kippur War broke out when Egypt and Syria attacked Israel in the afternoon on the Jewish holiday of Yom Kippur.
The attack pretty much took the Israeli intelligence by surprise. The feelings of power and superiority that the Israeli forces and leadership still felt from their victory in the Six-Day War, left a feeling of arrogance and the notion that no one will dare to attack, thus Israeli intelligence failed to foresee the attack.
Prior to the war, the Egyptian and Syrian armies, who were still traumatized by the complete defeat just six years earlier, continued building their armies and enhancing their power. These two countries and other Arab states who participated in the war received assistance from the Soviet Union (who wanted to establish power in the Middle East). Israel on the other hand began receiving assistance from her new best friend - the USA.
On October 6th, 1973, the afternoon of the Jewish Holiday, Yom Kippur, Egyptian and Syrian forces attacked at exactly 13:55 pm. The IDF took a few days to organize themselves from the surprise and prepare accordingly. The IDF had to defend from the attacks for four straight days, and that's when things began to change.
Israel managed to break through the Syrian line in the north and gained control of the Egyptian front down south. The Israeli attack took full throttle and the winds of victory seemed to change direction. The IDF began approaching Cairo and Damascus, and eventually, all sides were forced to sign the ceasefire on October 24th, just 19 days later.
There were many failures before the war and during it, mostly due to the lacking intelligence by the Israeli leadership. Israel lost 2,656 soldiers, and over 7,200 were wounded, 294 soldiers were taken hostage, and plenty of army vehicles, tanks, and planes were destroyed.
Nonetheless, Israel was still able to show her resilience, and overcome all of these failures and losses. The war is remembered as one of the toughest and hardest in Israeli history, but there were countless acts of heroism and courage to show what the Israeli spirit is made of.