I remember this phrase but I have not been able to locate it in the texts.
I do not recall the correct words but it's something like this: "Meditate/practice as if your hair is/were on fire".
"Practice like your hair is on fire!
A traditional aphorism, which probably goes back to Buddhism in India. Gelek Rinpoche makes it the theme of his recent article in Buddhadharma. And it shows up in the Zen tradition and elsewhere."
And this article says:
Zazen makes waiting into a science. I'm intrigued by the Zen injunction "Sit as if your hair were on fire."
Still no solution to the origin of the phrase. I'm looking for valid sources such as the Theravadan, East Asian and Tibetan texts.
Thank you for your time.