Devotee: "Such changes of body are meant for varieties of enjoyment or suffering by the living entity according to one's own work in this life. So Bhīṣma and Droṇa, being noble souls, were surely going to have either spiritual bodies in the next life, or at least life in godly bodies."
Prabhupāda: Yes. "Now, so far your grandfather is concerned, Bhīṣmadeva, he is one of the greatest devotees. So as soon as he gives up this body, he's going to Vaikuṇṭha." Same example as I told you the other day, that muni-putra . . . mā jīva mā jīva muni-putraka ciraṁ jīva rāja-putra: "Oh, the son of saintly person, you don't live. And oh, the son of a king, you live forever."
Why? Because the son of a saintly person, he is undergoing austerities, penances, disciplinary activities. So his life is . . . his future is so bright that he's going to Vaikuṇṭha. And this, the son of king, he's simply indulging in sense gratification. So he's going to hell. So the person who is destined to go to kingdom of God, the sooner he dies is better for him. And this person, one who is going to hell, the later he dies it is good for him, because as soon as he dies the hell is prepared for him.
A similarly, "Why should you lament for your grandfather and teacher? They are so highly elevated, spiritually elevated. Death will take place so long this body is there. Now they have come to fight as a matter of duty. So there is no lamentation." This is the instruction Kṛṣṇa is giving.