Here is an interesting passage from “The Conference of the Birds” by Farid ud-din Attar (Darbandi and Davis translation available from Penguin Books) that gives a beautiful image of combustion:
“A king with rivals in his dignity
Is no true king; the Simorgh rules alone
And entertains no rivals to his throne.
A king is not one of those common fools
Who snatches at a crown and thinks he rules.
The true king reigns in mild humility,
Unrivalled in his firm fidelity.
An earthly king acts righteously at times,
But also stains the earth with hateful crimes,
And then whoever hovers nearest him
Will suffer most from his destructive whim.
A courtier risks destruction every hour —
Distance yourself from kings and worldly power.
A king is like a raging fire, men say;
The wisest conduct is to keep away.”
There are three kings mentioned here.
The first is a mystical reference to God.
The second astrologically considered is a dignified Sun.
The last is a debilitated Sun.
The italicized couplet is combustion – a raging fire.