Bhagavad Gita is also known as Gitopaniṣad. It is the essence of Vedic knowledge and one of the most important Upanisads in Vedic literature.
Bhagavad Gita Introduction,
Cleanliness is essential for making advancement in spiritual life. There are two kinds of cleanliness: external and internal. External cleanliness means taking a bath, but for internal cleanliness one has to think of Krishna always and chant Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare. This process cleans the accumulated dust of past karma from the mind.
Bhagavad Gita 13.8-12,
Happiness derived from a combination of the senses and the sense objects is always a cause of distress and should be avoided by all means.
Bhagavad Gita 18.38,
Among all kinds of killers, time is the ultimate because time kills everything.
Bhagavad Gita 10.33,
One has to learn tolerance in the face of dualities such as happiness and distress, or cold and warmth, and by tolerating such dualities become free from anxieties regarding gain and loss.
Bhagavad Gita 2.45,
Those who have entered into a transcendental relationship with Krishna relish at every step the descriptions of the pastimes of the Lord.
Bhagavad Gita 10.18,