From Advaita Bodha Deepika (one of Ramana’s favourite traditional scriptures), Chapter 3:

17. Master: With complete stillness of mind, samsara will disappear root and branch. Otherwise there will be no end to samsara, even in millions of aeons (Kalpakotikala).

18. Disciple: Cannot samsara be got rid of by any means other than making the mind still?

M.: Absolutely by no other means; neither the Vedas, nor the shastras nor austerities, nor karma, nor vows, nor gifts, nor recital of scriptures of mystic formulae (mantras), nor worship, nor anything else, can undo the samsara. Only stillness of mind can accomplish the end and nothing else.

19. D.: The scriptures declare that only Knowledge can do it. How then do you say that stillness of the mind puts an end to samsara?

M.: What is variously described as Knowledge, Liberation, etc., in the scriptures, is but stillness of mind.

D.: Has any one said so before?

20-27. M.: Sri Vasishta had said…

Also from Chapter 3 of Advaita Bodha Deepika:

29-30. D.: How can the mind be made still?

M.: Only by Sankhya. Sankhya is the process of enquiry coupled with knowledge. The realised sages declare that the mind has its root in non-enquiry and perishes by an informed enquiry.

D.: Please explain this process.

M.: This consists of sravana, manana, nididhyasana and samadhi, i.e., hearing, reasoning, meditation and Blissful Peace, as mentioned in the scriptures. Only this can make the mind still.

31-32. There is also an alternative. It is said to be yoga.

D.: What is yoga?

M.: Meditation on Pure Being free from qualities.

D.: Where is this alternative mentioned and how?

M.: In the Srimad Bhagavad Gita, Sri Bhagavan Krishna has said: What is gained by Sankhya can also be gained by yoga. Only he who knows that the result of the two processes is the same, can be called a realised sage.

33-34. D.: How can the two results be identical?

M.: The final limit is the same for both because both of them end in stillness of mind. This is samadhi or Blissful Peace. The fruit of samadhi is Supreme Knowledge; this remains the same by whichever process gained.

From Ramana Maharshi’s ‘Who am I?’:

‘All the texts say that in order to gain release one should render the mind quiescent; therefore their conclusive teaching is that the mind should be rendered quiescent; once this has been understood there is no need for endless reading.’