Chapter 2 · The Yoga of Knowledge · Krishna said
Bhagavad Gita 2.28 — Unseen before and after
अव्यक्तादीनि भूतानि व्यक्तमध्यानि भारत। अव्यक्तनिधनान्येव तत्र का परिदेवना ॥
avyaktādīni bhūtāni vyaktamadhyāni bhārata | avyaktanidhanānyeva tatra kā paridevanā ||
Meaning
Beings are unseen before birth, seen in the middle, and unseen again after death. What is there to grieve about in this, Arjuna?