Lord Krishna broke his vow of not fighting the war, why did the Lord run to kill Bhishma Pitamah:

News Topical, Digital Desk : Bhishma Pitamah has been one of the great warriors of Mahabharata, who is known for religion, ethics and duty. He had also taken a vow of not marrying for life. It was because of this Bhishma pledge that he was named Bhishma. In the war of Mahabharata, he fought on behalf of the Kaurava army and played the role of the commander of the Kauravas.

so I broke my vow

During the war of Kurukshetra, Bhishma Pitamah was hell-bent on killing the Pandavas. Bhishma Pitamah had taken a vow that he would either kill all five Pandavas or force Lord Krishna to take up arms.

Arjuna was frightened to see his grandfather as his opponent and instead of fighting with him, he retreated. Seeing this, Shri Krishna broke his vow and got down from the chariot and picked up a wheel and ran to attack Bhishma Pitamah.

Why did Krishna take this decision?

Bhishma Pitamah knew that in this war the Pandavas were fighting for Dharma, while the Kauravas were supporting Adharma. Still, due to his vow, he was hell-bent on destroying the Pandavas. Whereas Arjun was reluctant to fight with Bhishma.

Then Lord Krishna felt that if he did not break his vow, it would lead to the defeat of Dharma and justice. Then Lord Krishna told Arjuna that "I have taken a vow not to take up arms in this war, but I am going to break this vow to kill Bhishma Pitamah".

Arjun gave this assurance

When Arjuna refused to face Bhishma, Lord Krishna became angry and ran to attack Bhishma. But Arjuna tried to stop him by holding the feet of the Lord. Then Arjuna assured Lord Krishna that he would fight the war with strength and face Bhishma Pitamah.