Lord Krishna - divine roles and appearance
Lord Krishna - Bhagvadgita - Took 30 minutes to preach entire bhagavad gita to Arjun on day 1 of the battle field of Kurukshetra (battle between righteousness (pandavas) and un-righteousness (Kauravas)), before start of battle.
Lord Krishna explained several aspects of the yoga, mystical knwledge, responsibility of human being on the earth.