Indra once hurled his
vajraayudha at vritraasura. But the weapon had no impact on him.
Sri
Brahma saw this and took the weapon and dipped it in his kamandalu and gave
it to Indra and asked him to use it after that. When Indra used the weapon
against vritraasura this time, the weapon was very powerful and wounded him
in several ways and was cutting his various limbs and organs of the body.
Seeing that his end was near, he wanted to take his revenge before his
death.
He thought that the pure water in which Sri Brahma had dipped the weapon was
the real power behind the weapon. So he decided to pollute all the waters
in the entire world. So he ran to all the waters sources and dipped his
bleeding body in them and thus defiling them to ensure that there was no
pure water anywhere.
Sri Brahma saw this and in order to prevent him from
defiling all water sources, he transformed the remaining pure water bodies
into darbha grass.
This is the reason for the darbha grass being treated on par with water as a
purifying agent.
There are situations where water cannot be used for
purifying. Under such circumstances darbha is used instead of water.
Ex:
When performing homa or yajna, the ghee that is to be offered is to be
purified. Obviously ghee cannot be washed with water. Instead, two darbha
grasses are taken and passed through the ghee and this purifies the ghee as
much as water would purify.
Another example: during eclipse we are supposed
to not cook and whatever is in the home should be washed. Items like
furniture, floor and bed can be washed with water. But long term food items
like pickles,
ghee, sugar, salt etc cannot be washed by water. Hence is the practice of
putting two pieces of darbha grass in all the food stuffs and here again,
darbha is believed to act as a purifier. pavitram [the adornment of the
ring finger during rituals] that is prepared from darbha grass is considered
important for completing the samkalpa without hindrance.
Source
"kurai onrum illai'
by Sri Mukkoor Lakshmi Narasimhacharya
