The Ādittasutta, commonly known as The Fire Sermon, is one of the most renowned teachings of the Buddha, delivered to a group of ascetics shortly after his enlightenment. The Buddha employs the metaphor of fire to describe the burning nature of human experience, emphasizing how the senses and their objects are aflame with passion, hatred, and delusion. This nicely encapsulates the essence of the Buddha's teachings on impermanence and non-attachment.

The Ādittasutta is found in the Connected Discourses on the Six Sense Bases; Saṁyutta Nikāya 35:28 .

"At one time the Buddha was staying near Gayā on Gayā Head together with a thousand mendicants. There the Buddha addressed the monks:

All is burning.

And what is the all that is burning?

The eye is burning. Sights are burning. Eye consciousness is burning. Eye contact is burning. The painful, pleasant, or neutral feeling that arises conditioned by eye contact is also burning. 

Burning with what?

Burning with the fires of greed, hate, and delusion. Burning with rebirth, old age, and death, with sorrow, lamentation, pain, sadness, and distress.

The ear … nose … tongue … body … mind ...

Thoughts are burning. Mind consciousness is burning. Mind contact is burning. The painful, pleasant, or neutral feeling that arises conditioned by mind contact is also burning. 

Burning with what? Burning with the fires of greed, hate, and delusion. Burning with rebirth, old age, and death, with sorrow, lamentation, pain, sadness, and distress, I say.

Seeing this, a learned noble disciple grows disillusioned with the eye, sights, eye consciousness, and eye contact. And they grow disillusioned with the painful, pleasant, or neutral feeling that arises conditioned by eye contact.

They grow disillusioned with the ear … nose … tongue … body … mind … painful, pleasant, or neutral feeling that arises conditioned by mind contact.

Being disillusioned, desire fades away. When desire fades away they’re freed. When they’re freed, they know they’re freed.

They understand: ‘Rebirth is ended, the spiritual journey has been completed, what had to be done has been done, there is no return to any state of existence.’ "

SOURCE TEXT: https://suttacentral.net/sn35.28/en/