Commentary on the Pitṛputra Samāgama Sūtra (36)

What is the fire element within the body?

Original text: Great King, what is the fire element within the body? If in this body, all that is perceived as warmth and heat, which causes the chewing and swallowing of food and drink to ripen, break down, and digest, thereby making the body peaceful and comfortable, that which belongs to the category of heat is called the fire element.

Explanation: The Buddha said: Great King, what is the fire element within the body? If in the body, all that can be felt as warmth and heat, which causes the chewing and swallowing of food and drink to ripen, break down, and digest, that is the fire element. After digestion, the body can be nourished, becoming peaceful and comfortable; these things that belong to the aspect of heat and thermal energy are the fire element.