Śrīla Śrīdhara Svāmī has pointed out that the word sva-rucā indicates that the nava-yogendras glowed from their own spiritual effulgence and not due to their ornaments or any other cause. The Supreme Soul, Lord Kṛṣṇa, is the original source of all light. His brilliantly glowing body is the source of the all-pervading brahmajyoti, the immeasurable spiritual light that is the resting place of innumerable universes (yasya prabhā prabhavato jagad-aṇḍa-koṭi). The individual soul, being part and parcel of the Lord, is also self-effulgent. In fact, everything in the kingdom of God is self-effulgent, as described in Bhagavad-gītā (15.6):

na tad bhāsayate sūryo
 na śaśāṅko na pāvakaḥ
yad gatvā na nivartante
 tad dhāma paramaṁ mama

It has already been described in many ways that the nava-yogendras were pure devotees of the Lord. Being completely Kṛṣṇa conscious souls, they naturally radiated the intense effulgence of the soul, as indicated here by the word sva-rucā. Śrīla Śrīdhara Svāmī has also pointed out that the word brahma-putropamān, meaning “equal to the sons of Brahmā,” indicates that the nava-yogendras were on the same spiritual platform as the four exalted Kumāra brothers. It has been described in the Fourth Canto that Mahārāja Pṛthu received the four Kumāras with great love and reverence, and here King Nimi is similarly receiving the nine sons of Lord Ṛṣabhadeva. Receiving exalted Vaiṣṇavas with love and reverence is standard spiritual etiquette for those who desire progress and happiness in life.