B.G 2.22
वासांसि जीर्णानि यथा विहाय नवानि गृह्णाति नरोऽपराणि। तथा शरीराणि विहाय जीर्णान्यन्यानि संयाति नवानि देही ॥ २-२२॥
vāsāṁsi jīrṇāni yathā vihāya navāni gr̥hṇāti narō'parāṇi। tathā śarīrāṇi vihāya jīrṇānyanyāni saṁyāti navāni dēhī ॥ 2-22॥
vāsāṁsi = cloths; jīrṇāni = worn out; yathā = the way; vihāya = casts off; navāni gr̥hṇāti = wears new ones; naraḥ aparāṇi = the being; tathā śarīrāṇi = similarly; vihāya jīrṇāni = gives up worn out; anyāni saṁyāti = takes up others; navāni dēhī = new body;
Just as a person casts off worn-out clothes and puts on new ones, similarly the being gives up worn-out bodies and takes up other bodies that are new.
Gīta Tātparya 2.22
Union and separation of the body from the soul is birth and death, respectively. There is no need to grieve for the same.
जीवस्यापि शरीरसंयोगवियोगावेव जनिमृती यतः ततो न दुःखकारणमित्याह। वासांसीति ॥ २२ ॥
jīvasyāpi śarīrasaṁyōgaviyōgāvēva janimr̥tī yatastatō na duḥkhakāraṇamityāha। vāsāṁsīti ॥ 22 ॥
[jīvasyāpi = Even jīva; śarīra saṁyōga viyōgāvēva = has union and separation with the body; janimr̥tī yataḥ = in the form of birth and death; tatō na duḥkha kāraṇam = and it should not be the reason to grieve; ityāha vāsāṁsīti = so stated in the verse 'vāsāṁsīti'.]
Even jīva has union and separation with the body in the form of birth and death. The verse 'vāsāṁsīti' clarifies that it should not be the reason to grieve.