Classical Vedanta · part of the Mahabharata
Bhagavad Gita 13.33
One sun lights the whole world; one Self lights the whole field
यथा प्रकाशयत्येकः कृत्स्नं लोकमिमं रविः। क्षेत्रं क्षेत्री तथा कृत्स्नं प्रकाशयति भारत॥
As the one sun illuminates this entire world, so does the one Self illuminate the entire field of matter.
What this verse points to
The sun does not become the things it illuminates, and it is not divided among them. It stays what it is while everything else becomes visible. The verse applies that relation to awareness and experience.
This is the most useful thing to remember when a sit goes badly. Whatever is being lit — noise, boredom, a racing mind — the light itself is not any of those things and is not damaged by them.
Sit with it
When the sit is unpleasant, shift from the content to what is aware of it, and check whether the awareness is also unpleasant.
About the Bhagavad Gita
The Bhagavad Gita is a 700-verse dialogue set on the battlefield of Kurukshetra, in which Krishna counsels the warrior Arjuna at the moment he refuses to fight. Across eighteen chapters it draws together the paths of action, devotion, and knowledge into a single teaching on how to act without being bound by action. It sits inside the Bhishma Parva of the Mahabharata and has been the most widely commented-upon text in the Vedantic tradition, from Shankara onward.
References to this text are given as chapter.verse — here, 13.33.