But know that inertia is born of ignorance, deluding all embodied beings; it binds, O Bhārata!, through heedlessness, laziness and sleep.

Tamas originates in ajñāna — ignorance of the true Self. Its effect is mohana — delusion, confusion, the obscuration of clear perception.

Three doors of tamas: pramāda (heedlessness, carelessness), ālasya (laziness, lethargy), and nidrā (sleep, unconsciousness). These prevent spiritual practice.

The tamasic person is bound by inertia, unable to initiate change or pursue liberation. Breaking free from tamas requires the activation of rajas.