sa rāmabhavanaṃ prāpya pāṇḍurābhraghanaprabham| tisraḥ kakṣyā rathenaiva viveśamunisattamaḥ
Having crossed the three courtyards in the chariot, that foremost of ascetics (Vasistha) entered Rams's abode, shining like a mass of white clouds.
— M.N. Dutt (1891)
Vasistha crosses three courtyards in his chariot to reach Rama's abode. The three thresholds mark a progression from the public world of the court to the private world of the prince. The sage enters like a messenger of destiny — which he is.