Sri Krishna convinces Arjuna with His three-level approach to continue with the dharma-yuddha. This forms the essence of His teaching in Chapter 2 of Bhagavad Gita.
Philosophical level- atma-anatma viveka
Ethical level- dharma-adharma viveka
Worldly angle- Laukika level
The philosophical argument is covered in verses 12 to 25 of chapter 2. This is gives the core teaching of vedanta in a nut-shell. Further elaboration will continue in subsequent chapters.