This is very famous in many of Nochur Talks.
Even Sri Lakshmana Swamy mentions in his biography that by reading this single verse, he got a direct experience of Self and understood the core of maharishi teachings.
this first originated with jagadeesvara sastri.
हृदयकुहरमध्ये केवलं ब्रह्ममात्रं
ह्यहमहमिति साक्षादात्मरूपेण भाति |
हृदि विश मनसा स्वं चिन्वता मज्जता वा
पवनचलनरोधादात्मनिष्ठो भव त्वम् ||
Once, Jagadīśvara-śāstri composed the first line of the above verse in the mālini metre but was unable to complete it. He left the incomplete verse with the Maharśi and went away for a short break. By the time Jagadīśvara-śāstri came back, the Maharśi had added the rest of the lines and even put in his signature as ?Jagadīśa?. Jagadīśvara-śāstri was surprised looking at the now complete verse. He asked the Maharṣi if he knew who had completed it . The Maharṣi replied with a smile ? ?it was Jagadīśa who did it?. It was then that the meaning of Maharṣi?s words dawned upon Śāstri.