Bhagavad Gita Chapter 2 Verse 33

atha cettvamimaṃ dharmyaṃ saṅgrāmaṃ na kariṣyasi
tataḥ svadharmaṃ kīrtiṃ ca hitvā pāpamavāpsyasi

But, if you will not fight this righteous war, then, having abandoned your own duty and fame, you shall incur sin.

atha = therefore; cet = if; tvaṃ = you; imaṃ = this; dharmyaṃ = as a religious duty; saṃgrāmaṃ = fighting; na = do not; kariṣyasi = perform; tataḥ = then; svadharmaṃ = your religious duty; kīrtiṃ = reputation; ca = also; hitvā = losing; pāpaṃ = sinful reaction; avāpsyasi = will gain.;