देही नित्यमवध्योऽयं देहे सर्वस्य भारत | तस्मात्सर्वाणि भूतानि न त्वं शोचितुमर्हसि ||२-३०||
dehī nityamavadhyo.ayaṃ dehe sarvasya bhārata . tasmātsarvāṇi bhūtāni na tvaṃ śocitumarhasi ||2-30||
Chapter 2 · Verse 30
Sankhya Yoga
सांख्ययोग
In plain words
You are being commanded to rise above your sorrow for any living being. While physical bodies are temporary and will perish, the true self residing within everyone is eternal and can never be destroyed. Armed with this jnana, or sacred spiritual knowledge, you can find the strength to let go of your grief and see the immortal truth in everyone.
Translation
2.30 The self in the body, O Arjuna, is eternal and indestructible. This is so in the case of the selves in all bodies. Therefore, it is not fit for you to feet grief for any being.
Meaning
The body of any creature may be destroyed but the Self cannot be killed. Therefore you should not grieve regarding any creature whatever. Bhishma or anybody else.
Word by word
देही indweller नित्यम् always अवध्यः indestructible अयम् this देहे in the body सर्वस्य of all भारत O Bharata तस्मात् therefore सर्वाणि (for) all भूतानि creatures न not त्वम् thou शोचितुम् to grieve अर्हसि (thou) shouldst.