Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 18: The Advent of Rāma, Lakṣmaṇa, Bharata and Śatrughna
Text 1.18.26

तेषां केतुरिव ज्येष्ठो रामो रतिकरः पितुः।
बभूव भूयो भूतानां स्वयम्भूरिव सम्मतः॥

teṣāṁ ketur iva jyeṣṭho rāmo ratikaraḥ pituḥ
babhūva
bhūyo bhūtānāṁ svayambhūr iva sammataḥ

teṣām = among Daśaratha’s sons; ketuḥ = a flag [broadcasting the glory of His dynasty]; iva = like; jyeṣṭhaḥ = the eldest son; rāmaḥ = Rāma; ratikaraḥ = pleasing; pituḥ = to His father; babhūva = became; bhūyaḥ = most; bhūtānām = for all living beings; svayam-bhūḥ = the self-born Brahmā; iva = like; sammataḥ = and an object of constant love.

Among Daśaratha’s sons, the eldest son Rāma like a flag [broadcasting the glory of His dynasty] became most pleasing to His father and an object of constant love for all living beings, like the self-born Brahmā.

Rāma was described as a mahātmā hereinbefore. Now that is described in detail.