yan-nimittaḥ sa vai śāpo
yādṛśo dvija-sattama
katham ekātmanāṁ bheda
etat sarvaṁ vadasva me
yat-nimittaḥ - arising by what cause; saḥ - that; vai - indeed; śāpaḥ - curse; yādṛśaḥ - what kind; dvija-sat-tama - O purest of twice-born brāhmaṇas; katham - how; eka-ātmanām - of those who shared the same soul (Śrī Kṛṣṇa); bhedaḥ - the disagreement; etat - this; sarvam - all; vadasva - please tell; me - to me.
Ekātmanām means that the Yadus all shared the same opinion, namely that Kṛṣṇa, the Supreme Personality of Godhead, was the goal of their life. Therefore, Parīkṣit Mahārāja could not see any obvious reason for such a destructive quarrel among the members of the Yadu dynasty, and he was anxious to know the actual cause.