• brahmaṇya-devaḥ — the Lord considerate to the brāhmaṇas
  Compound: brahmaṇya (devoted to brāhmaṇas) + deva (Lord). One of Kṛṣṇa's defining epithets in the Bhāgavata (cf. namo brāhmaṇya-devāya). His treatment of this messenger illustrates the title in operation.
• avaruhya — getting down (from the throne)
  Absolutive of ava-√ruh (to descend). The exact gesture of brahmaṇyatā — Bhagavān unseats Himself to honor His brāhmaṇa-guest. Gauḍīya practice still mirrors this: the host stands and gives the higher seat to the visiting Vaiṣṇava.
• arhayām cakre — He performed worship
  Periphrastic perfect of √arh (to worship). The same root that gives arghya — the Vedic offering of water to an honored guest. Kṛṣṇa formally worships the brāhmaṇa with full Vedic protocol, despite being the worshipped of all the devatās.
• yathā ātmānam diva-okasaḥ — just as the residents of heaven worship Himself
  Phrase. The simile is deliberately steep — Kṛṣṇa worships the brāhmaṇa in the same manner that the devas worship Kṛṣṇa. Gauḍīyas mark this as the Lord's modeling of Vaiṣṇava-sevā for all His servants forever after.

• Where do you under-honor brāhmaṇical visitors because of your own seated position?
• Could you step down to seat someone the Lord would step down to seat?

Kṛṣṇa descends from His golden throne to seat a Vidarbha brāhmaṇa — the Lord whom devatās worship now standing up to honor a Vedic guest. The descent from the throne is the working physics of brahmaṇya: Bhagavān's favorite ornament is to be the brāhmaṇas' servant.