In plain words
Kṛṣṇa told exactly this to Gāndhārī, the wife of Dhṛtarāṣṭra, so that it went straight into her heart. After the hundred Kauravas died, Kṛṣṇa went to soothe her grief. He went to offer His sympathy, poor soul. When she heard the news that Kṛṣṇa was coming, Gāndhārī, in great rage, consumed with anger and sorrow, nursed her hatred. In sorrow the discernment of good and bad becomes void. Right into it anger enters. Through anger comes hatred. Through hatred and anger comes envy too. She had bound her eyes. ‘Mother, Kṛṣṇa has come,’ said her companions. Grieving, this Gāndhārī says, ‘Kṛṣṇa! How partial You are! You are a deceiver. The Pāṇḍavas and the Kauravas are the children of brothers. Kindness to one, and such unkindness to the other? That may be. Of the five Pāṇḍavas, all five survived. Could You not have spared even one of my sons? Could You not have kept even one alive to offer the funeral rice-balls? Why did Your divine sight not fall on even one?’ Kṛṣṇa is always ready with a smile. Another's sorrow is Ānanda to Him.
He takes away tears, He brings on tears; He makes the enjoyer a renunciant, He makes the renunciant an enjoyer.
Why bring on tears, why take away tears? In keeping with the parts each one plays. At this moment He gave her, beautifully, a truth to feel, which Gāndhārī had not understood. ‘Gāndhārī! I know you have a hundred sons. But did you see even one son with your own eyes? Merely because everyone says you have a hundred sons, you too imagine that you have a hundred sons. You did not see even one son with your eyes. Wicked ones who were not worthy even of the sight of the mother who bore them: how can they be worthy of the sight of God?’ Do you see? People who were not worthy even of the sight of the mother who bore them: how can they be worthy of the sight of God? When your sight was not on them, how could true Prema for them arise? So your sons are wicked ones, not worthy of their mother's sight. They went on hating those whose form is eternal and true, those vowed to Satya. The Pāṇḍavas are righteous souls. Your unrighteous sons would not listen however much they were told, and set their hatred on them. They have no power of inquiry at all. They are full to the brim with selfishness alone. Through that very selfishness they have come to this end. By justice the kingdom belongs to the Pāṇḍavas alone! Because the children were young, they made your husband a guardian. But to cheat these little children who trusted him so much …!