In plain words
In the same way, every man must carry out his duty. They said, ‘Duty is God.’ Do your duty. Carry out your own duty. Once, a great assembly was being held. Into this assembly came the Pāṇḍavas, the Kauravas, kings, haters: everyone. In that full court, Śiśupāla and Dantavaktra kept reviling Kṛṣṇa most basely. They kept criticising Dharmarāja, saying the first honour must not be given to Kṛṣṇa. Are there no gurus in this assembly greater than this Kṛṣṇa? Many yogis, sages, great ascetics and men who have renounced every attachment are present in this assembly. Not only that: the ācāryas, who practise and live it. Droṇācārya and all these are here. Bhīṣmācārya is surely greater than this one! When such ācāryas are here, why should the first honour go to this Kṛṣṇa?
For stealing the saris of the young women as they bathed, is it for that you get worship? The day you frolicked in the water with the lovely cowherd girls, is arghya offered for the delight you took? Enough now, put away your almanac; do not go on praising; stop, shut your mouth! This tongue is not enough to praise Śrī Kṛṣṇa? I will split your mouth into a hundred strips, you there, Bhīṣma!
In many such ways they kept reviling him. Dharmaja could not bear to hear these insults. His mind fell into unrest in all kinds of ways. Even as all looked on, Kṛṣṇa flung the plate on which He had received the first honour at Śiśupāla, just once. Not the discus, not Sudarśana: He threw only the plate. That plate went and took off Śiśupāla's head. Dharmaja was glad at that. But the very next moment, Śiśupāla's blood went and fell on Kṛṣṇa's feet. His life's light merged in Kṛṣṇa. This sight astonished Dharmaja all the more!