Sivavakkiyar was a 9th century CE Tamil mystic, one of the Siddha poet-saints of the Shaivite tradition of South India. Nothing is known of his life, but the surviving collection of his poems speaks of direct knowledge of the Truth, without need for rules, rituals and forms.

What is that you call a temple?
And what is that which you consider
a sacred pond?
Those who worship
such temples and ponds, listen –
the sacred temples and ponds are all
within your heart.
There is no such thing
as birth and death.