While Lord Brahma was consulting the other demigods at the top of Sumeru Hill, I (Narada Muni) was also present with my stringed instrument, the vina

Expressions researched:
"While Lord Brahma was consulting the other demigods at the top of Sumeru Hill, I was also present with my stringed instrument, the vina"

SB Canto 10.1 to 10.13

Nārada was a friend of the King of heaven, and thus he told Kaṁsa, the son of Ugrasena, "My dear hero, you have satisfied me with a proper reception, and therefore I shall tell you something secret and confidential. While I was coming here from Nandakānana through the Caitraratha forest, I saw a great meeting of the demigods, who followed me to Sumeru Parvata. We traveled through many holy places, and finally we saw the holy Ganges. While Lord Brahmā was consulting the other demigods at the top of Sumeru Hill, I was also present with my stringed instrument, the vīṇā. I shall tell you confidentially that the meeting was held just to plan to kill the asuras, headed by you. You have a younger sister named Devakī, and it is a fact that her eighth son will kill you."

SB 10.1.69, Purport:

An additional verse in this chapter of Śrīmad-Bhāgavatam is accepted by the Madhvācārya-sampradāya, represented by Vijayadhvaja Tīrtha. The verse is as follows:

atha kaṁsam upāgamya

nārado brahma-nandanaḥ

ekāntam upasaṅgamya

vākyam etad uvāca ha

atha—in this way; kaṁsam—unto Kaṁsa; upāgamya—after going; nāradaḥ—the great sage Nārada; brahma-nandanaḥ—who is the son of Brahmā; ekāntam upasaṅgamya—after going to a very solitary place; vākyam—the following instruction; etat—this; uvāca-said; ha—in the past.

Translation: "Thereafter, Nārada, the mental son of Lord Brahmā, approached Kaṁsa and, in a very solitary place, informed him of the following news."

The great saint Nārada descended from the heavenly planets to the forest of Mathurā and sent his messenger to Kaṁsa. When the messenger approached Kaṁsa and informed him of Nārada's arrival, Kaṁsa, the leader of the asuras, was very happy and immediately came out of his palace to receive Nārada, who was as bright as the sun, as powerful as fire, and free from all tinges of sinful activities. Kaṁsa accepted Nārada as his guest, offered him respectful obeisances and gave him a golden seat, brilliant like the sun. Nārada was a friend of the King of heaven, and thus he told Kaṁsa, the son of Ugrasena, "My dear hero, you have satisfied me with a proper reception, and therefore I shall tell you something secret and confidential. While I was coming here from Nandakānana through the Caitraratha forest, I saw a great meeting of the demigods, who followed me to Sumeru Parvata. We traveled through many holy places, and finally we saw the holy Ganges. While Lord Brahmā was consulting the other demigods at the top of Sumeru Hill, I was also present with my stringed instrument, the vīṇā. I shall tell you confidentially that the meeting was held just to plan to kill the asuras, headed by you. You have a younger sister named Devakī, and it is a fact that her eighth son will kill you." (reference: Hari-vaṁśa, Viṣṇu-parva 1.2-16)

No one can blame Nāradajī for encouraging Kaṁsa to kill the sons of Devakī. The saint Nārada is always a well-wisher for human society, and he wanted the Supreme Personality of Godhead, Kṛṣṇa, to descend to this world as soon as possible so that the society of demigods would be pleased and would see Kaṁsa and his friends killed by Kṛṣṇa. Kaṁsa would also attain salvation from his nefarious activities, and this too would very much please the demigods and their followers. Śrīla Viśvanātha Cakravartī Ṭhākura remarks in this connection that Nārada Muni sometimes did things that were beneficial to the demigods and the demons simultaneously. Śrī Vīrarāghava Ācārya, in his commentary, has included the following half-verse in this regard: asurāḥ sarva evaita lokopadrava-kāriṇaḥ. Asuras are always disturbing elements for human society.