Everyone has a different nature.
It is what it is.
It is neither good nor bad.
Our nature is made of a combination of Sattva, Rajas, Tamas. All three gunas come from God. There is need for all three. You can't make a meal with sugar alone. You need herbs and spices of all types - sweet, sour, bitter, smelly and scented to make a tasty meal.
If the Universe was full of Sattva
alone, it would be dull and boring.
If the Universe was full of Rajas alone, it would be terribly competitive and selfish.
If the Universe was full of Tamas alone, it would be pure hell.
God has designed the universe so that it is a delicate balance of Sattva, Rajas and Tamas. Everything is in the right place, in the right proportion, at the right time. Those of us who can't see the 'big picture' see the universe as a chaotic place with random acts of violence, creation, destruction, grace and miracle. Not knowing the divine design, we can't appreciate the 'lila' (play) of the Lord.
Day is needed for us to do 'work'.
Night is needed for us to 'rest'.
If day persisted forever, we would tire of work and have no way to hide from heat and light.
If night persisted forever, we would tire of the darkness and curse every time we stub our toes on stones and roots.
World is perfect just the way it is.
We have to rise above judgment of right and wrong to see that. Seeing the world as it is – full of contradictions and quarrels and appreciate its underlying, unifying cord, is Jyana Yoga. To understand that electrons, protons and neutrons make up the atoms of all elements – from hydrogen and oxygen, lead and silver, plutonium and gold is knowledge. To appreciate that electrons are just as individual as the elements they make up, is Jyana Yoga.
Shri Krushna sees this. That’s why he understands that Shishupal-the-soul is essentially pure and also appreciates that Shishupal-the-person is evil. For sake of the world, Shri Krushna appreciates the need to remove evil from the world without harming the souls of evil people. Hence Shri Krushna liberates the souls of all the people He kills. God is truly merciful. There is no perpetual hell for anyone – not even the likes of Shishupal, Kans or Putna.
Knowing right from wrong is easy from our own perspective. Knowing who is actually right and who is really wrong is difficult without seeing the big picture. It is easy to get confused and blame our inaction on this confusion. Seeing through the cloud of confusion and choosing the right course is Karma Yoga. For example, a mother may insist her child eats at one time and at another time refuse them food. This apparent dichotomy of action is easier to understand if know WHY the mother is doing this – illness, age, waiting for dinner time, corrective behavior etc may account for her contradicting actions. Knowing exactly what to do, when to do it and with who is Karma Yoga.
That’s why Shri Krushna can appreciate the contradictions and confusions of Bhishma and Drona’s actions and inaction throughout the Mahabharata. He also knows the nature of Duryodhan and knows what can and can’t be achieved through sama, dama, danda and bhed. Knowing what the right action is at the right time is Karma Yoga.
Dedication to a cause or an idea or a person is what gives our life a purpose. Who or what we are dedicated to is often dependent on our nature, nurture as well as our karmic bonds to people and places. Our Bhakti (dedication) Yoga determines what we are passionate about in life. Our passions often dictate the direction of our life.
Knowing this, Shri Krushna exhorts Arjun to dedicate his life to Him. Arjun and Krushna have a karmic connection going back several lifetimes. Dedicated to upliftment of mankind, they have both taken several incarnations (eg Nara & Narayan) to help humans at different periods of time. Knowing this, Shri Krushna reminds Arjun of their joint aim of lightening the load off mother Earth and disposing evil from the world. Arjun, by his nature, is inclined to the same aims in life as himself and so Shri Krushna reminded him to be his bhakta (joined / dedicated / devotee).