Ramana Maharshi

 The truth of oneself alone is worthy to be scrutinized

and known. Taking it as the target of one's attention, one should keenly know it in the Heart. This knowledge of oneself will be revealed only to the consciousness which is silent, clear and free from the activity of the agitated and suffering mind. Know that the consciousness which always shines in the Heart as the formless Self 'I', and which is known by one's being still without thinking about anything as existent or non-existent, alone is the perfect reality.