Srimad-Bhagavatam: Canto 6 - Chapter 1 - Verse 55
येन प्रसुप्त: पुरुष: स्वापं वेदात्मनस्तदा ।सुखं च निर्गुणं ब्रह्म तमात्मानमवेहि माम् ॥ ५५ ॥
yena prasuptaḥ puruṣaḥsvāpaṁ vedātmanas tadāsukhaṁ ca nirguṇaṁ brahmatam ātmānam avehi mām
Know Me to be the Supreme Brahman, the all-pervading Supersoul through whom the sleeping living entity can understand his dreaming condition and his happiness beyond the activities of the material senses. That is to say, I am the cause of the activities of the sleeping living being.
When the living entity becomes free from false ego, he understands his superior position as a spirit soul, part and parcel of the pleasure potency of the Lord. Thus, due to Brahman, even while sleeping the living entity can enjoy. The Lord says, “That Brahman, that Paramātmā and that Bhagavān are I Myself.” This is noted by Śrīla Jīva Gosvāmī in his Krama-sandarbha.