This is a brief sub-gloss. For a fuller reading of this verse, see Madhusūdana, Śaṅkara, or Rāmānuja above.

And tamas, the third quality, know to be born of ignorance, arisen from ignorance; it deludes, makes for delusion, the want of discernment, in all the embodied. By heedlessness, sloth and sleep it binds, that tamas, O Bhārata. The working of the qualities is now told in brief.

What is other than knowledge is here meant by 'ignorance'; knowledge is the awareness of the truth of a thing, and what is other than that, the knowledge that is its contrary, is tamas, which is born of the knowledge whose object is the contrary of the truth of a thing and is the deluder of all the embodied. Delusion is contrary knowledge; the meaning is that tamas is the cause of contrary knowledge. It binds the embodied one by being the cause of heedlessness, sloth, and sleep, and so by their door. Heedlessness is the inattention that is the cause of engagement in something other than the action that is to be done. Sloth is the nature of not undertaking actions, that is, stiffness. Sleep is, through the weariness of the working of the senses, the ceasing of the working of all the senses; in it the ceasing of the working of the outer senses is dream, and the ceasing of the working of the mind too is deep sleep. The Lord states the chief among the doors of bondage of sattva and the rest.

This is a brief sub-gloss. For a fuller reading of this verse, see Madhusūdana, Śaṅkara, or Rāmānuja above.

Tamas is 'born of ignorance' (ajnanaja) in the sense that ignorance arises from it, as the rest of the sentence shows, 'heedlessness and delusion from tamas' (14.17).