The important verses about Krishna written in Bhagwat Gita.

athama
I and you and others were present in earlier years also and shall be present in future years also. These bodies are parishable. Atman or Krishna can not be destroyed. Atman is not active, can not be cut, can not be vatted or dried. It is omnipresent and stationary. It can not be changed. All creations were without body before birth and without body after birth.

tatwa
Universe is part of Cosmos. Universe and cosmos can not be separated and so can not be destroyed. He , who knows meaning of Tatwa written in the Vedas or Books or Shashtra , knows Universe in reality. Brahma creates Devta, Human Being and Tiryak ( Birds, Animals, Reptiles , movable or non movable etc ). Since when it exists and till what period it may continue is not known. One should be free from desires ( Vasana ), attractions ( Mamta) and should try to find Param Ishwar or Param Atman. One should work hard. Area which can not receive light from Sun and Moon is where I live. ( This may be an indication that Atman is not part of skin. It may be heart or inside heart). Jeev Atman is part of my Atman. Jeev Atman attracts Tri Gun Maya. Mind and 5 Indriyan are attracted by Tri Gun Maya".Beautiful simlie is narrated here.

indriyan
As Air takes smell from one place to the other place, in the same way Jeev Atman takes mind and 5 indriyan to other body which it receives. ( Verse no 8 of Chapter 15 of bagavadgeeta). Knowledgeable persons know this theory of life. They know that Jeev Atman leaves one body and go to the other body fixed for Atman. Intelligent person tries and knows that Atman is situated in the heart of creation. Heat of Sun or Fire is part of my heat. My heat only enters in to earth and helps to grow vegetations or medicinal plants. With my heat in human body 4 types of different foods are digested. Body of human being is perishable and Jeev Atman is not perishable. Any person, who knows my theory of life, is intelligent person. Oh Arjun I have told you very secretive knowledge ."
satwik In chapter 16 of Gita-Krishna says " Now i shall explain you regarding Devic Wealth and Asuri Wealth. A person who is fearless, pure from inside, trying to know theory of life , Satwik donation, Control on desires, worshiping and performing good actions, not harming any one with words, body , or mind, truthful words, without anger or control on anger, feeling of no action done by me, Pardon, tolerance, no enmity all the said characteristics are of persons having Devic Wealth.

desireOh Arjun Pride, Anger, Harsh words, are characteristics of persons of Asuri Wealth. Devi Wealth gives Moksha and Arjun you are having Devic wealth. Human being with Asuri nature person says that there is no God and world is created by combination of Men and women and human being should enjoy luxuries, fighting for wine, women and wealth and I have succeeded and I am the best . I shall do and I shall enjoy and attracted to wards desires and sex. These person get hell. Such type of persons get again and again Asuri Yoni. Sex, anger, greed takes a person to hell. So one should control desires and should achieve Param Gati."
kama artha There is connection between sex, anger and greed to instability of mind or brain. If one does not control sex, anger and greed then one may always get depressed. Sex , anger and greed are like fire. One can never be satisfied. There is no limit of wine drinking, women consuming, or wealth possessing. It all creates jealousy, hatred, anger and mind can never be stable. If mind is unstable or unsatisfied , it emits special type of electrons and all these electrons creates different amino acids and all this creates unhappiness. These are not the characteristics of scientist. Knowledge of Tatwa can not be gained by unstable mind. So to know theory of Tatwa or life one must work hard and should have control on desires and work hard and should be free from desires or craze to get more money or wealth. It does not mean that sex or wealth or wine is not good. One should work or act but should not be part of actions. All actions are part of destiny. So It is state of mind " doing actions but not involving in these actions" ( Involve means doing action without caring for results) bagavad gita