Bg 18.39

yad agre cānubandhe ca
sukhaṁ mohanam ātmanaḥ
nidrālasya-pramādotthaṁ
tat tāmasam udāhṛtam
Synonyms: 
yat — that which; agre — in the beginning; ca — also; anubandhe — at the end; ca — also; sukham — happiness; mohanam — illusory; ātmanaḥ — of the self; nidrā — sleep; ālasya — laziness; pramāda — and illusion; uttham — produced of; tat — that; tāmasam — in the mode of ignorance; udāhṛtam — is said to be.
Translation: 
And that happiness which is blind to self-realization, which is delusion from beginning to end and which arises from sleep, laziness and illusion is said to be of the nature of ignorance.
Purport: 

One who takes pleasure in laziness and in sleep is certainly in the mode of darkness, ignorance, and one who has no idea how to act and how not to act is also in the mode of ignorance. For the person in the mode of ignorance, everything is illusion. There is no happiness either in the beginning or at the end. For the person in the mode of passion there might be some kind of ephemeral happiness in the beginning and at the end distress, but for the person in the mode of ignorance there is only distress both in the beginning and at the end.