Verse 6.1.1

॥ षष्ठोऽध्यायः ॥
श्वेतकेतुर्हारुणेय आस तं ह पितोवाच श्वेतकेतो वस ब्रह्मचर्यं न वै सोम्यास्मत्कुलीनोऽननूच्य ब्रह्मबन्धुरिव भवतीति ॥ ६.१.१ ॥

|| ṣaṣṭho'dhyāyaḥ ||
śvetaketurhāruṇeya āsa taṃ ha pitovāca śvetaketo vasa brahmacaryaṃ na vai somyāsmatkulīno'nanūcya brahmabandhuriva bhavatīti || 6.1.1 ||

1. Āruṇi had a son named Śvetaketu. Once Āruṇi told him: ‘Śvetaketu, you should now live as a brahmacārin. No one in our family has not studied the scriptures and has not been a good brāhmin’.

Word-for-word explanation:

Śvetaketuḥ ha Āruṇeyaḥ āsa, Āruṇi had a son named Śvetaketu; tam ha pita uvāca, his father said to him [to Śvetaketu]; śvetaketo, O Śvetaketu; vasa brahmacaryam, live as a brahmacārin [i.e., a celibate student]; na vai somya asmat kulīnaḥ, no one in our family, my child; ananūcya, has not studied the scriptures; brahma-bandhuḥ iva bhavati iti, and has not been a good brāhmin.

Commentary:

Om.

The word brahma-bandhu literally means a relative or friend of a brāhmin—in other words, one who is a brāhmin in name only.

The question arises here, why did Āruṇi himself not invest his son with the sacred thread, initiating him into the life of a brahmacārin? Why did he suggest that his son go to another brāhmin for his sacred thread and for his education and training? Śaṅkara says, it is likely that Āruṇi was about to start on a journey and would be away from home for some time, and that is why he decided to send his son to another brāhmin.