Bhagavad Gita · 2.21

वेदाविनाशिनं नित्यं य एनमजमव्ययम्।कथं स पुरुषः पार्थ कं घातयति हन्ति कम्॥

vedāvināśhinaṁ nityaṁ ya enam ajam avyayam kathaṁ sa puruṣhaḥ pārtha kaṁ ghātayati hanti kam

O Partha, how can a person who knows the soul to be indestructible, eternal, unborn, and immutable kill anyone or cause anyone to kill?

— Bhagavad Gita 2.21

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)