One verse

Bhagavad Gita 2.33

2.33

अथ चेत्त्वमिमं धर्म्यं संग्रामं न करिष्यसि | ततः स्वधर्मं कीर्तिं च हित्वा पापमवाप्स्यसि ||२-३३||

atha cettvamimaṃ dharmyaṃ saṃgrāmaṃ na kariṣyasi . tataḥ svadharmaṃ kīrtiṃ ca hitvā pāpamavāpsyasi ||2-33||

atha
therefore
cet
if
tvam
you
imam
this
dharmyam
as a religious duty
saṅgrāmam
fighting
na
do not
kariṣyasi
perform
tataḥ
then
sva-dharmam
your religious duty
kīrtim
reputation
ca
also
hitvā
losing
pāpam
sinful reaction
avāpsyasi
will gain

If, however, you do not perform your religious duty of fighting, then you will certainly incur sins for neglecting your duties and thus lose your reputation as a fighter.