Agni is our essence. We are fire, fire is us.
From the original teachings, the Rg Veda, the god of fire, Agni, was addressed in the opening hymn. Agni is the original force of who and what we are.
With respect to fire, use the analogy of a fireplace; if you don't look after the fire it will not last. Similarly, your inner fire must be tended to with care and consideration.
Ayurveda, the sister science to yoga, also known as the science of life, addresses fire by way of pitta dosha. You address pitta/fire with diet and lifestyle choices to ultimately get the fire to its optimal level.
Too much pitta equals acid reflux, rashes, loose stool, burning eyes, and many other symptoms in the body. In the mind anger, agitation, rudeness, assertiveness, judgment, etc. occur when there's too much fire.
The sharpness of pitta isn't pleasant when in abundance both for the person living with it and the folks around them.
Foods that increase pitta are spicy, fried, acidic, fermented, including too much caffeine and alcohol. You counter these qualities by replacing these with foods that are more cooling in nature. Foods with sweet, bitter and astringent tastes are recommended.
Lifestyle choices affect pitta as well. When there are too many projects on the go and a lot of intensity that's the sign of a heightened pitta. Saying no to more projects, getting more down-time, getting into nature, staring up at the moon - these are all ways you counter high pitta via lifestyle choices.
On the alchemy side, fire is a transformational force. This plays out in the way you practice, what you are doing to take you from where you are now to the place of your true potentiality. The agni within transforms.
Use asana, pranayama, meditation and agni sara to burn off the dross and energy that is stuck within you - mental and emotional scaring for example. Work in the gut area to address fire, even though fire is throughout your being, at the cellular level, the but is primary. Churn the belly with agni sara.
You want to remember who you truly are. You are a spiritual being having an earthly experience. You are more than the sum of your body, your mind, your thoughts. You are part of the cosmic level of fire and it is part of you.
Greater discernment is the result of this work so you make better choices in your life to bring you to your higher Being.
From this spiritual perspective, it is working from the perspective that when on the mat I'm doing more than stretching. I'm honouring my body, via my doshas in what I eat and do, this will bring me forward. When evolving as a human fire is making the transformation happen.