nivārito nāradena
tat-sutau mṛtyum ātmanaḥ
jñātvā loha-mayaiḥ pāśair
babandha saha bhāryayā
nivaritah -- checked; naradena -- by Narada; tat-sutau -- his two sons; mrityum -- death; atmanah -- his own; jnatva -- understanding; loha-mayaih -- made of iron; pasaih -- with shackles; babandha -- he bound up (Vasudeva); saha -- together with; bharyaya -- his wife.
But Narada restrained Kamsa by reminding him that it was the two sons of Vasudeva who would cause his death. Kamsa then had Vasudeva and his wife shackled in iron chains.
Kamsa realized that there was no use in killing Vasudeva, since it was Vasudeva's sons, Krishna and Balarama, who were to kill him. According to the acaryas, Narada also advised Kamsa that if he killed Vasudeva the two young boys might flee and that it was therefore better not to kill him. Rather, Narada recommended, Kamsa should bring Krishna and Balarama to Kamsa's capital city, Mathura.
Srila Visvanatha Cakravarti points out that Narada did not act inimically toward the great devotees Vasudeva and Devaki when he revealed this information to Kamsa. In fact, as explained in the Eleventh Canto, Vasudeva was grateful to Narada because he was arranging for Kamsa's death at Krishna's hands, and further arranging for Krishna to come and live in Mathura, where His loving father could associate with Him.
