harer aṁśāv ihāgatau
bhāra-vyayāya ca bhuvaḥ
tau — both; imau — these; vai — certainly; bhagavataḥ — of the Supreme Personality of Godhead; hareḥ — of Hari; aṁśau — part and parcel expansion; iha — here (in this universe); āgatau — has appeared; bhāra-vyayāya — for mitigation of the burden; ca — and; bhuvaḥ — of the world; kṛṣṇau — the two Kṛṣṇas (Kṛṣṇa and Arjuna); yadu-kuru-udvahau — who are the best of the Yadu and Kuru dynasties respectively.
That Nara-Nārāyaṇa Ṛṣi, who is a partial expansion of Kṛṣṇa, has now appeared in the dynasties of Yadu and Kuru, in the forms of Kṛṣṇa and Arjuna respectively, to mitigate the burden of the world.
Nārāyaṇa is the Supreme Personality of Godhead, and Nara is a part of the Supreme Personality of Godhead, Nārāyaṇa. Thus the energy and the energetic together are the Supreme Personality of Godhead. Maitreya informed Vidura that Nara, the portion of Nārāyaṇa, had appeared in the family of the Kurus and that Nārāyaṇa, the plenary expansion of Kṛṣṇa, had come as Kṛṣṇa, the Supreme Personality of Godhead, with the purpose of delivering suffering humanity from the pangs of material burdens. In other words, Nārāyaṇa Ṛṣi was now present in the world in the forms of Kṛṣṇa and Arjuna.