Bhagavad Gita · 2.27

जातस्य हि ध्रुवो मृत्युर्ध्रुवं जन्म मृतस्य च।तस्मादपरिहार्येऽर्थे न त्वं शोचितुमर्हसि॥

jātasya hi dhruvo mṛtyur dhruvaṁ janma mṛtasya cha tasmād aparihārye 'rthe na tvaṁ śhochitum arhasi

For one who is born, death is certain; and for one who dies, birth is certain. Therefore, you should not grieve over the inevitable.

— Bhagavad Gita 2.27

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