Bhagavad Gita

ನಿಯತಂ ಕುರು ಕರ್ಮ ತ್ವಂ ಕರ್ಮ ಜ್ಯಾಯೋ ಹ್ಯಕರ್ಮಣಃ ।
ಶರೀರಯಾತ್ರಾಪಿ ಚ ತೇ ನ ಪ್ರಸಿದ್ಧ್ಯೇದಕರ್ಮಣಃ॥೮॥
niyataṃ kuru karma tvaṃ karma jyāyo hyakarmaṇaḥ |
śarīrayātrāpi ca te na prasiddhyedakarmaṇaḥ||8||

Gist of the sloka:
Do your prescribed duty for you. Action is better than in-action. Without action life does not progress.
Lord Krishna says, you must do your duties which is according your swabhava but with the right knowledge. Here Arjuna is known for fighting evil forces all along in his life. He has a long history of protecting the subjects against harm. This is his natural behavior - swabhava.
Arjuna instead if he starts on the path of gynana which is not his natural character, when the evil forces are aligned against the populace, it would be betraying his duty and would not be right yoga.
Lord Krishna teaches that one should therefore never be without action. Do your duty with correct knowledge. Whatever is achieved/result out of such actions, receive it as blessings from the Lord. Be aware of the Lord always with the belief that the action/karma is undertaken by you, is due the grace of Lord. When we realize that, results of such action belong to the Lord; such actions will never become binding on you or result in attachment. Such actions elevate you.
Do your duty. Whatever comes receive it as blessings. Never lose the sight of Lord feet,
Lord Hari is the supreme. Lord Hari is the refuge of gurus.
Lord Hari is the father and mother of this universe.
As long as we are in this body, action is inevitable. Even when we receive enlightenment or right knowledge, actions are inevitable. Lord Krishna gave his theory of karma yoga in this verse.
We also need to realize one more truth. Scriptures indicate karmas create attachments and stop the progress of our souls. One action leads to another and we will be trapped in the karmic cycle. Lord also tells that inaction is not possible and action is must. How else can we escape from this cycle? The next verse gives better clarity on this.