Sankhya Karika Verse 55
Sanskrit Verse
तत्र जरामरणकृतं दुःखं प्राप्नोति चेतनः पुरुषः । लिङ्गस्याविनिवृत्तेः, तस्माद् दुःखं स्वभावेन ॥ ५५ ॥
Transliteration
tatra jarāmaraṇa kṛtaṃ duḥkhaṃ prāpnoti cetanaḥ puruṣaḥ | liṅgasya avinivṛtteḥ tasmāt duḥkhaṃ svabhāvena ||
Translation
Therein does intelligent Purusa experience pain caused by decay and death, on acount of the non-cessation of, or till the cessation of, the Subtile Body : wherefore pain is the natural order of things.
Reference: Sankhya Karika

Muni's Play