Devibhagavatapurana 4.1.41

4.1.41

duḥkhaṃ mahattaraṃ prāptāḥ pūrvajanmakṛtena vai |
devāṃśānāṃ kathaṃ teṣāṃ saṃśayo'yaṃ mahānhi me ||

If it be urged, that they suffered so many serious calamities, due to their actions in their former lives, that seems impossible. Because they are born of the Devas; thus arises my doubt; be pleased to explain to me.
Again how the Pândavas, the sons of Kunti, of good conduct, and knowing the illusory nature of the world, why did they, out of pretence kill Bhîsma, Drona and others?