There once lived a sage who was descended from the great saint Bhrigu. This sage performed intense austerities and acquired formidable powers. Since he consumed only fruits and later only green leaves, he came to be called Parda.
THE VOICE WITHIN
Sage Parda continued his intense spiritual exercises and all the animals and plants in the forest lived under his benevolent control. Once while cutting some long grass to repair his hermitage, the sage cut his middle finger. But to his surprise, instead of blood he saw tree sap oozing through the cut.
Sage Parda now thought he had become so pious and exalted of his physical body that pure sap had replaced his blood. Filled with pride, he began to think there was no more spiritual goal left for him to achieve.
Having witnessed everything, Lord Shiva divined what was in sage Parda’s heart. He took the guise of an old man and reached the hermitage. Before long, sage Parda was telling him about the pride he felt that the pure sap of fruits and trees were now flowing through his body, which was surely the result of his long austerities.
The old man then asked him what was there to be proud of. “It may not be blood anymore, but it is still sap. When trees and plants are burned, they turn into ash. Only ash remains filly, which is why it is the highest stage,” he said.
The old man then sliced his finger and ash began to emerge from the cut. Bewildered, sage Parda now meditated upon the strange visitor in front of him. At once he realized it was none else than Lord Shiva. Utterly overwhelmed, he prayed for forgiveness for his ignorance.
It is said that ever since then Lord Shiva wears ash to remind his devotees of the Ultimate Reality, and the foolishness of getting emored of worldly accomplishments. The ash symbolises destruction, for veritably Lord Shiva is the Destroyer of the Universe.
But ash also signifies immutability for it is created by burning things, yet cannot be burnt itself. It thus stands for permanence of the immortal soul, which is released when matter is destroyed.
— the harbinger