Filled with egoism, if you think, I will not fight vain in this, your resolve; (for) nature will compel you.

yat = if; ahaṅkāraṃ = of false ego; āśritya = taking shelter; na yotsye = I shall not fight; iti = thus; manyase = you think; mithyaiṣaḥ = this is all false; vyavasāyaḥ = determination; te = your; prakṛtiḥ = material nature; tvāṃ = you; niyokṣyati = will engage.;