Rohitassa (“red horse”) is Agni in his manifestation as the swift sunbeam, breaking over the mountains and flashing across the sky. Agni was he of red horses (rohidaśva, Rig Veda 1.45.2, 4.1.8, 8.43.16, 10.7.4, 10.98.9; see 2.10.2). This can mean the tongues of the ritual fire whose message is speedily conveyed to the gods, but especially the “ruddy steed” swift as the wind (aruṣā rohitā, 1.94.10), the “red horses of the dawn” (aruṇebhir aśvair, Rig Veda 1.113.14, see 4.52.2, 6.65.2, 7.75.6). The current Sutta seems to draw on the conception of Rohita in Atharvaveda 13, glorifying Agni as the Sun, who “arrives in a flash” (13.2.15), “swift” (13.2.2), “rushing” (13.2.19), “traversing the sky” (13.2.22), radiating as far as worlds extend (13.2.42, 13.2.10, 13.1.16), racing over the world never letting his thought stray (13.2.15). The “Sun’s bay horses” (sūryasyāśvā harayaḥ, 13.1.24) are seven ruddy steeds who carry it, spreading out its rays (13.2.4, 13.3.16).

The coming of the dawn was greeted with priestly gifts offered by benefactors (bhoja). These benefactors may be the Aṅgīrasas, shining poets who ushered in the dawn (RV 3.53.7), or else the Aśvins, horse deities driving the Sun’s chariot and close with the Sun’s daughter (4.43.2, 8.8.2), or the dawns themselves (4.51.3, 7.79.3, 8.25.21).

Taught as a parable by the Buddha to two brahmin cosmologists (lokāyatikā) at AN 9.38:4.1.

It has been pointed out that a swift arrow can fly at 250 f/s, which would take 0.008 seconds to cross the width of a palm trunk of two feet. India ocean to ocean is about 2400 km. To cross it in 0.008 seconds would require a velocity of around 300,000 km/s—the speed of light.

This echoes Śatapatha Brāhmaṇa 1.2.5.14 and 7.1.1.37, where the fire altar is measured out as a fathom (vyāmamātra) for this is the length of a human. The altar and the human person encompass the whole world.