श्री भगवानुवाच अशोच्यानन्वशोचस्त्वं प्रज्ञावादांश्च भाषसे। गतासूनगतासूंश्च नानुशोचन्ति पण्डिताः ॥

aśhochyān-anvaśhochas-tvaṁ prajñā-vādānśh cha bhāṣhase gatāsūn-agatāsūnśh-cha nānuśhochanti paṇḍitāḥ

Thou grievest for those that should not be grieved for, yet speakest words of wisdom. The wise grieve neither for the living nor for the dead.

In plain words: Krishna tells Arjuna that he is grieving for people he does not need to grieve for, even though he talks like a wise man. Wise people do not grieve for the living or for the dead.