Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 8

Sanskrit:

यदा स्वनिगमेनोक्तं द्विजत्वं प्राप्य पूरुष: ।यथा यजेत मां भक्त्या श्रद्धया तन्निबोध मे ॥ ८ ॥

ITRANS:

yadā sva-nigamenoktaṁdvijatvaṁ prāpya pūruṣaḥyathā yajeta māṁ bhaktyāśraddhayā tan nibodha me

Translation:

Now please listen faithfully as I explain exactly how a person who has achieved twice-born status through the relevant Vedic prescriptions should worship Me with devotion.

Purport:

The word sva-nigamena refers to the particular Vedic injunctions relevant to one’s social and occupational status. Members of the brāhmaṇa, kṣatriya and vaiśya communities all achieve dvijatvam, twice-born status, by initiation into the Gāyatrī mantra. Traditionally, fully qualified brāhmaṇa boys may be initiated at age eight, kṣatriyas at eleven and vaiśyas at twelve, provided the proper conditions are met. Having achieved twice-born status, one should faithfully worship the Supreme Personality of Godhead in His form of the Deity, as the Lord Himself will describe.