Mbh 11.8.2b

Through that king, thy purpose will be achieved. For his sake, many kings will assemble together on the field of Kuru. Capable of smiting, they will cause one another to be slain through the instrumentality of hard weapons. It is evident, O goddess, that thy burthen will then be lightened in battle. Go quickly to thy own place and continue to bear the weight of creatures, O beauteous one!" From this thou wilt understand, O king, that thy son Duryodhana, born in Gandhari's womb, was a portion of Kali, sprung for the object of causing a universal slaughter. He was vindictive, restless, wrathful, and difficult of being gratified. Through the influence of Destiny his brothers also became like him. Shakuni became his maternal uncle and Karna his great friend. Many other kings were born on earth for aiding in the work of destruction. As the king is, so do his subjects become. If the king becomes righteous, even unrighteousness (in his dominions) assumes the shape of righteousness. Servants, without doubt, are affected by the merits and defects of their masters. Those sons of thine, O king, having obtained a bad king, have all been destroyed. Conversant with truth, Narada, knew all this. Thy sons, through their own faults, have been destroyed, O king! Do not grieve for them, O monarch! There is no cause for grief. The Pandavas have not, O Bharata, the least fault in what has happened. Thy sons were all of wicked souls. It is they that caused this destruction on earth. Blessed be thou; Narada had truly informed Yudhishthira of all this in his court on the occasion of the rajasuya sacrifice, saying, "The Pandavas and the Kauravas, encountering each other, will meet with destruction. Do that, O son of Kunti, which thou shouldst!" Upon these words of Narada, the Pandavas became filled with grief. I have thus told thee that which is an eternal secret of the gods.