Bhagavad Gita · Sankhya YogaChapter 2, Shloka 11 (2.11)

The first sentence — a contradiction. Krishna shows Arjuna a contradiction within himself: you are grieving, and also talking wisdom. Shankaracharya: "you are displaying two opposite things in yourself at once — foolishness and learning — like someone deranged."

"Prajñāvādān" — which words? Ramanuja clarifies: words of Arjuna's such as "pitaro patanti" — "the ancestors fall" (1.42) — which rest on knowledge of a self distinct from the body and of the next world. That is, on one side Arjuna accepts that the self survives the body (the fall of the ancestors), and on the other he grieves over the destruction of bodies. This is the contradiction.

For whom is there no grief? Gatāsūn agatāsūṃś ca — for both the dead and the living. Ramanuja gives a subtle reading here: gatāsu = bodies (which are lifeless, inert), agatāsu = selves — one who knows the nature of both grieves for neither. Shankaracharya: Bhishma, Drona and the others are not to be grieved for — because of their good conduct, and because in the highest sense they are eternal.

Is Krishna being harsh? On the surface it seems Krishna is denying the sorrow. But his aim is to show Arjuna the cause: your sorrow rests on a mistaken understanding. The next shlokas will correct that understanding.