SB 1.6.29

kalpānta idam ādāya
 śayāne ’mbhasy udanvataḥ
śiśayiṣor anuprāṇaṁ
 viviśe ’ntar ahaṁ vibhoḥ
Synonyms: 
kalpa-ante — at the end of Brahmā’s day; idam — this; ādāya — taking together; śayāne — having gone to lie down; ambhasi — in the causal water; udanvataḥ — devastation; śiśayiṣoḥ — lying of the Personality of Godhead (Nārāyaṇa); anuprāṇam — breathing; viviśe — entered into; antaḥ — within; aham — I; vibhoḥ — of Lord Brahmā.
Translation: 
At the end of the millennium, when the Personality of Godhead, Lord Nārāyaṇa, lay down within the water of devastation, Brahmā began to enter into Him along with all creative elements, and I also entered through His breathing.
Purport: 

Nārada is known as the son of Brahmā, as Lord Kṛṣṇa is known as the son of Vasudeva. The Personality of Godhead and His liberated devotees like Nārada appear in the material world by the same process. As it is said in the Bhagavad-gītā, the birth and activities of the Lord are all transcendental. Therefore, according to authorized opinion, the birth of Nārada as the son of Brahmā is also a transcendental pastime. His appearance and disappearance are practically on the same level as that of the Lord. The Lord and His devotees are therefore simultaneously one and different as spiritual entities. They belong to the same category of transcendence.