evam jnaatvaa kritam karma poorvairapi mumukshubhihi |
kuru karmaiva tasmaattvam poorvaih poorvataram kritam || 15 ||

Even seekers of freedom, having known this (path of karmayoga), performed actions since ancient times. Therefore, so do you perform actions like the ancients did.

evam : this manner
jnaatvaa : having known
kritam : performed
karma : actions
poorvaih : since ancient times
api : even
mumukshubhihi : seekers of freedom
kuru : perform
karma : actions
eva : those
tasmaat : therefore
tvam : you
poorvaih : ancestors
poorvataram : since ancient times
kritam : actions

Previously, Shri Krishna explained that one who knows him as distinct from performer and enjoyer of actions is not bound. Now, he reaffirms that teaching by informing Arjuna that many ancient seekers of freedom have followed the path of karmayoga.

These ancient seekers understood that the “I” is the eternal essence. It is not the doer and does not have anything to gain from results of actions. So they continued to perform actions, dedicating them to the highest ideal which is Ishvaraa, and purified their minds doing so.

Shri Krishna also re-emphasizes that this teaching did not deter the ancient seekers from performing actions, in other words, they did not abandon their duties and retire to the forest. They continued to work in the world but maintained the karmayoga attitude.

By pointing out the heritage of karmayoga, Shri Krishna constantly reminded Arjuna that this is not a brand new teaching, it always was a way of life but was lost due to the passage of time.