The yogi and mystic Sri Ramana Maharshi taught a very clear form of self inquiry. The verses here are from Sri Ramana’s translation from Sanskrit of a work entitled ‘Self Realization’ in which Lord Shiva instructs his son Kartikeya.

Shiva says :

Meditate ever on that
Which is beyond the reach of the mind,
Allowing no refuge for the mind.
The joy that is attained in abundance in that Self,
That is beyond all verities and complete.

Without any differences, and beyond the reach of thinking,
Without any precedent, without anything similar,
That which is the utmost frontier and extolled as the supreme bliss,
Be immersed in it.