Śrī brahma-saṁhitā 5.27
gāyatrīṁ gāyatas tasmād
dvijatām agamat tataḥ
atha — then; veṇu-ninādasya — of the sound of the flute; trayī-mūrti-mayī — the mother of the three Vedas; gatiḥ — the means (the Gāyatrī mantra); sphuranti — being made manifest; praviveśa — entered; āśu — quickly; mukha-abjāni — the lotus faces; svayambhuvaḥ — of Brahmā; gāyatrīm — the Gāyatrī; gāyataḥ — sounding; tasmāt — from Him (Śrī Kṛṣṇa); adhigatya — having received; saroja-jaḥ — the lotus-born (Brahmā); saṁskṛtaḥ — initiated; ca — and; ādi-guruṇā — by the primal preceptor; dvijatām — the status of the twice-born; agamat — attained; tataḥ — thereafter.
Then Gāyatrī, mother of the Vedas, being made manifest, i.e. imparted, by the divine sound of the flute of Śrī Kṛṣṇa, entered into the lotus mouth of Brahmā, born from himself, through his eight ear-holes. The lotus-born Brahmā having received the Gāyatrī, sprung from the flute-song of Śrī Kṛṣṇa, attained the status of the twice-born, having been initiated by the supreme primal preceptor, Godhead Himself.
The sound of Kṛṣṇa's flute is the transcendental blissful sound; hence the archetype of all Veda, is present in it. The Gāyatrī is Vedic rhythm. It contains a brief meditation and prayer. Kāma-gāyatrī is the highest of all the Gāyatrīs, because the meditation and prayer contained in it are full of the perfect transcendental sportive activities which are not to be found in any other Gāyatrī. The Gāyatrī that is attained as the sequel of the eighteen-lettered mantra is kāma-gāyatrī which runs thus: klīṁ kāma-devāya vidmahe puṣpa-bāṇāya dhīmahi tan no 'naṅgaḥ pracodayāt. In this Gāyatrī, the realization of the transcendental pastimes of Śrī Gopījana-vallabha after perfect meditation and the prayer for the attainment of the transcendental god of love are indicated. In the spiritual world there is no better mode of endeavor for securing the superexcellent rasa-bedewed love. As soon as that Gāyatrī entered into the ear-holes of Brahmā, he became the twice-born and began to chant the Gāyatrī. Whoever has received the same Gāyatrī in reality, has attained his spiritual rebirth. The status of a twice-born that is obtained in accordance with one's worldly nature and lineage, by the fettered souls in this mundane world, is far inferior to that of the twice-born who obtains admission into the transcendental world; because the initiation or acquisition of transcendental birth as a result of spiritual initiation is the highest of glories in as much as the jīva is thereby enabled to attain to the transcendental realm.