Happy indeed are the KSHATRIYAS, O Partha, who are called to fight in such a battle, that comes of itself as an open-door to heaven.

yadṛcchayā = by its own accord; ca = also; upapannaṃ = arrived at; svarga = of the heavenly planets; dvāraṃ = door; apāvṛtaṃ = wide open; sukhinaḥ = very happy; kṣatriyāḥ = the members of the royal order; pārtha = O son of Pritha; labhante = do achieve; yuddhaṃ = war; īdṛṣaṃ = like this.;