Bhagavad Gita 2.27

जातस्य हि ध्रुवो मृत्युर्घ्रुवं जन्म मृतस्य च |
तस्माद्परिहार्येऽर्थे न त्वं शोचितुमर्हसि

Translation

Death is certain for one who has been born, and rebirth is inevitable for one who has died. Therefore, you should not lament over the inevitable.