Kuntī could understand that "Although Kṛṣṇa is playing the part of human being, He is for everyone's good. He simply presents. As enemy or as friend, it is beneficial." Either He is playing the part of enemy or as friend, it is the same thing because He is absolute. In the Absolute world there is no such thing: "This is good; this is bad." Everything good in the absolute world. Kṛṣṇa's killing is as good as Kṛṣṇa's saving. It is the same thing.
So Kuntī could understand. The devotees can understand. So He has no partiality. Nobody should misunderstand that Kṛṣṇa has got partiality, no. This partiality and enmity, friendliness, these are material, duality. Here we cannot understand good unless there is bad. Therefore it is called relative world. We cannot understand father unless there is son. We cannot understand good man unless there is bad man. So these things, duality or relative world, they should exist in this material world. Therefore in order to approach to the spiritual world one should become above this duality, above this duality. This duality means the intermixture of the modes of material nature, traiguṇya. The Sanskrit word is traiguṇya. So Kṛṣṇa advised Arjuna, nistraiguṇyo bhavārjuna. Traiguṇya-viṣayā vedā nistraiguṇyo bhavārjuna. So how one can become above these nistraiguṇya, er, traiguṇya? You... Simply by devotional service, unalloyed devotional service.