how was the whole mahabharat war stopped just during conversation between krisna & arjuna.?

You might check out this link:

http://www.quora.com/Mahabharata-Hindu-epic/Why-would-the-Kaurava-army-wait-patiently-while-Krishna-rendered-Bhagavad-Gita-to-Arjuna-in-the-battle-field?page_id=3

The whole maha bharath is a trash Except Krishna and Krishnas Words

Hear only words of Krishna Thats what Bhagavad GIta Is