Has any advaitic teacher said that learning advaita only at the word level is useless?

Question

The 4 Mahakavyas or Great saying of Advaita Vedanta are as follows:

1. Prajñānam Brahma (प्रज्ञानम् ब्रह्म) - "Insight is Brahman," or "Brahman is insight” - (Aitareya Upanishad 3.3 of the Rig Veda)
2. Ayam Ātmā Brahma (अयम् आत्मा ब्रह्म) - "This Self (Atman) is Brahman" - (Mandukya Upanishad 1.2 of the Atharva Veda)
3. Tat Tvam Asi (तत् त्वम् असि) - "That essence (tat, referring to sat, "the Existent" are you" - (Chandogya Upanishad 6.8.7 of the Sama Veda)
4. Aham Brahmāsmi (अहम् ब्रह्मास्मि) - "I am Brahman - (Brihadaranyaka Upanishad 1.4.10 of the Yajur Veda)

The above sayings can all be learnt verbally very easily.

Meaning on one hand learning the Mahakavyas and the philosophy is easy, but to actually experience the Mahakavyas and realise their truth is a different case and requires enormous energy. A realised advaitic teacher can be felt as a highly energetic presence (with Brahmatejas).

Thus, have traditional advaitic teachers said that learning Advaita philosophy only at the word level (merely mugging up the Mahakavyas without understanding/experiencing the truth) is useless?

Answer 1

From the Vivekachudamani of Adi Sankaracharya -

na gacchati vinā pānaṃ vyādhirauṣadhaśabdataḥ | vināparokṣānubhavaṃ brahmaśabdairna mucyate || 62 ||

62. A disease does not leave off if one simply utter the name of the medicine, without taking it; (similarly) without direct realisation one cannot be liberated by the mere utterance of the word Brahman.

akṛtvā dṛśyavilayamajñātvā tattvamātmanaḥ | brahmaśabdaiḥ kuto muktiruktimātraphalairnṛṇām || 63 ||

63. Without causing the objective universe to vanish and without knowing the truth of the Self, how is one to achieve Liberation by the mere utterance of the word Brahman? -- It would result merely in an effort of speech.

akṛtvā śatrusaṃhāramagatvākhilabhūśriyam | rājāhamiti śabdānno rājā bhavitumarhati || 64 ||

64. Without killing one’s enemies, and possessing oneself of the splendour of the entire surrounding region, one cannot claim to be an emperor by merely saying, ‘I am an emperor’.