Purport

In this Shloka Bhagvan Shri Krishna gives yet another practical aspect of the action. There are many people in society who cannot understand the intricacies of the concept of Karma. They do hard work to get worldly success. This may not be the best way to achieve liberation from the material world, but it is better than doing nothing or doing the wrong things.

Telling such people to leave the desires for fruits may confuse such people as very desires of fruits drive them to perform actions. It is very difficult for normal people to understand how to renounce their desires while still having the dedication towards actions.

Those who are enlightened or leaders should not deliver blind speeches but rather set an example by performing the actions without attachment to fruits. Divine concepts of karma can be explained better by setting an example by performing karma than delivering speeches.