Below is verse 357 from Shankara’s Vivekachudamani together with Swami Chinmayananda’s brief commentary on the verse, stating the need for Samadhi, and how without this experience the whole of written and verbal vedanta is just empty talk. BMI is Swami Chinmayananada’s shorthand for Body-Mind-Intellect:

Also see:

The Union of Meditation and Self-Enquiry – The two paths of Vedanta – Panchadasi by Vidyaranya Swami

Advaita Bodha Deepika – vital teachings for Self-Realisation that are often missing in modern non-dual and advaitic teachings

Ramana Maharshi: the path to self-realisation (Padamalai)

Shankara on the Mind, Samadhi (stillness of mind), Manonasa (destruction of mind), and Liberation