तमस्त्वज्ञानजं विद्धि मोहनं सर्वदेहिनाम्।प्रमादालस्यनिद्राभिस्तन्निबध्नाति भारत॥
tamas tv ajñāna-jaṃ viddhi mohanaṃ sarva-dehināmpramādālasya-nidrābhis tan nibadhnāti bhārata
Word by word
The verse says
Know that heaviness is born of not knowing, and it confuses everyone who lives in a body. It binds by carelessness, by laziness, and by sleep, Arjuna.
In plain words
Three forms: pramāda, ālasya, nidrā.
Carelessness, laziness, sleep. The least glamorous verse in the chapter.
And the root is ajñāna-ja — born of not knowing. Not of wickedness. Of a kind of fog.
Where you've felt this · in health
After something difficult, a week comes when you cannot make yourself answer an email that would take four minutes. You are not resting and you are not busy. The email sits there. Each day makes it slightly harder, for no reason you could name.
Going deeper
Describing inertia as a force rather than a failure is more accurate than how most people treat it in themselves.
Tamas is not the absence of the other two. It is its own strand, with its own momentum, and it binds as actively as drive does. That matters because the ordinary response to it — deciding to try harder — treats it as a vacuum that willpower can fill, and anyone who has been in it knows that is not how it behaves.
The chapter will say later that all three rise and fall by turns, each one displacing the others.
Which is the more useful way to meet a flat week. Something is currently dominant; it is not a verdict on your character; and it will be displaced, by the ordinary rotation the next verses describe, whether or not you manage to be impressive about it.