SB 10.86.45

yathā śayānaḥ puruṣo
 manasaivātma-māyayā
sṛṣṭvā lokaṁ paraṁ svāpnam
 anuviśyāvabhāsate
Synonyms: 
yathā — as; śayānaḥ — sleeping; puruṣaḥ — a person; manasā — with his mind; eva — alone; ātma — own; māyayā — by his imagination; sṛṣṭvā — creating; lokam — a world; param — separate; svāpnam — dream; anuviśya — entering; avabhāsate — he appears.
Translation: 
The Lord is like a sleeping person who creates a separate world in his imagination and then enters his own dream and sees himself within it.
Purport: 

In the illusion of his dream, a sleeping person creates an apparent world, complete with cities populated by the fictional products of his imagination. In somewhat the same way, the Lord manifests the cosmos. Of course, the creation is not illusory for the Lord, but it is for those souls who are put under the control of His Māyā potency. As her service to the Lord, Māyā deludes the conditioned souls into accepting as real her temporary, insubstantial manifestations.