aprakaashopravrittishcha pramaado moha eva cha |
tamasyetaani jaayante viviriddhe kurunandan || 13 ||

Darkness, inaction, heedlessness and also error. These arise when tamas is predominant, O descendant of the Kurus.
aprakaashaha : darkness
apravrittihi : inaction
cha : and
pramaadaha : heedlessness
mohaha : error
eva : also
cha : and
tamasi : of tamas
etaani : these
jaayante : arise
viviriddhe : predominant
kurunandan : O descendent of the Kurus
Shri Krishna addressed Arjuna as “kurunandana” when explaining the marks of tamas, but addressed him as “bharatarshabha” when explaining the marks of rajas. He was probably hinting that some members of the Kuru dynasty, the Kauravas, were under the influence of tamas. When we are under the influence of tamas, we make erroneous decisions. We become inert like a stone, resorting to inaction. Even when we act, it is out of heedlessness. Our knowledge is covered by tamas, creating darkness within us.
Let us go deeper into what inaction really means. When we have a lack of drive to achieve anything in the world, when we wants to escape all sense of responsibilities, when all ambitions go away, that is inaction. Moha, error or delusion is even worse. We cannot accurately judge our relationship with the world, with other people, with our family, our friends, our job and so on. We become a “good for nothing”, and will remain in that state unless someone wakes us up.
Nature has its own scale of tamas, rajas and sattva. It is better to crawl like an insect than lie around like a stone, better to work like an ant rather than crawl like an ant, better to pollinate flowers like a bird than simply work like an ant, better to give milk to others like a cow than pollinate flowers like a bird, and it is better to work with one’s intellect like a human than to give milk to others like a cow. So one who is steeped in tamas, should start to act, even if the actions are without any planning or thinking, just to get into a higher mental state.