Otherwise, you cannot be able to kill him. This is the time. This is the opportunity. You kill him." Because Karṇa was greater hero than Arjuna. Dronācārya, Bhīṣma... That is explained by Parīkṣit Mahārāja, that "In the battlefield of Kuru, just like a ocean, and there were big, big crocodiles, animals, like Dronācārya, Bhīṣma, Karṇa. But by the grace of Kṛṣṇa, my grandfather was able to kill them." Arjuna was not so strong that he could kill Bhīṣma or Dronācārya, Karṇa. They were greater heroes. So these things are there.
There, there are many instances. Just like gopīs. At dead of night, when Kṛṣṇa's flute was there, they left their husband, left their father, left their brothers, children, everything, and they went away. Now, according to our Vedic system, young girls, young women, leaving the protection of father, brother or superiors, and going in the forest for another boy—oḥ, it is very sinful. Socially, it is sinful. And Kṛṣṇa instructed them, "What you have done? You go back immediately."