eta mūrti-bheda kari’ kṛṣṇa-sevā kare
kṛṣṇera śeṣatā pāñā ‘śeṣa’ nāma dhare

“He (Lord Baladeva) is thus called Lord Śeṣa, for He has attained the ultimate end of servitude to Kṛṣṇa. He takes many forms for the service of Kṛṣṇa, and thus He serves the Lord.” [CC Ādi 5.124]

chatra, pādukā, śayyā, upādhāna, vasana
ārāma, āvāsa, yajña-sūtra, siṁhāsana

“He serves Lord Kṛṣṇa, assuming all the following forms: umbrella, slippers, bedding, pillow, garments, resting chair, residence, sacred thread and throne.” [CC Ādi 5.123]

Because the Mṛdaṅga is used in Kṛṣṇa’s service, it is respected as nondifferent in nature from Śrī Baladeva Prabhu, Kṛṣṇa’s elder brother in Vraja-līlā. Also, since Lord Nityānanda and Lord Balarāma are nondifferent, we can also understand that the Mṛdaṅga is nondifferent from the most merciful Lord Nityānanda Prabhu.