Prabhupada's lecture - Śrīmad-Bhāgavatam 1.8.26 - Māyāpura, October 6, 1974

So this is the illusion. Therefore śāstra says, ato gṛha-kṣetra-sutāpta-vittair janasya moho 'yam. Janasya moho 'yam ahaṁ mameti [SB 5.5.8]. How a man becomes entangled in this material world, everything is described in the Śrīmad-Bhāgavatam. Puṁsaḥ striyā mithunī-bhāvam etam. This material world means sex attraction, mithunī-bhāva. The man is searching after woman; woman is searching after man. This is material life, in human life, in bird's, beast's... Just these sparrows—they are trying to make some nest on this chandelier to enjoy sex and lay eggs. Therefore they require some place.

The basic principle is sex. First of all sex life, then other necessities. First of all, seeing, man and woman. Then, when they unite, puṁsaḥ striyā mithunī-bhāvam etaṁ tayor mitho hṛdaya-granthim āhuḥ [SB 5.5.8]. When they unite and they get children, then the hard knot of heart—"She, my wife. She's (He's) my husband. We cannot separated..." Hard knot. Hṛdaya-granthi. Already there is attraction. Now this attraction becomes more and more tight, after unity. Then we require a place to live together, "Home, sweet home." Yes, very sweet. The whole day and night, work. And this is moha. He is working hard day and night. There is not a single moment leisure, and still, he's: "Sweet home." This is illusion.