Devibhagavatapurana 4.11.36

4.11.36

sajjā bhavantu yuddhāya saṃrabdhāḥ śastrapāṇayaḥ |
śatruśchidreṇa hantavya eṣa dharmaḥ sanātanaḥ ||

Be ready now and dress yourself with your arms and ammunitions, “Lo! Whenever you get any loop hole in your enemies, catch hold of it and kill your enemy.” This is the eternal religion.