O Supreme Personality of Godhead, there are ten prescribed methods on the path to liberation — to remain silent, not to speak to anyone, to observe vows, to amass all kinds of Vedic knowledge, to undergo austerities, to study the Vedas and other Vedic literatures, to execute the duties of varṇāśrama-dharma, to explain the śāstras, to stay in a solitary place, to chant mantras silently, and to be absorbed in trance. These different methods for liberation are generally only a professional practice and means of livelihood for those who have not conquered their senses. Because such persons are falsely proud, these procedures may not be successful.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
मौनव्रतश्रुततपोऽध्ययनस्वधर्म- व्याख्यारहोजपसमाधय आपवर्ग्याः । प्रायः परं पुरुष ते त्वजितेन्द्रियाणां वार्ता भवन्त्युत न वात्र तु दाम्भिकानाम्
maunavrataśrutatapo'dhyayanasvadharma- vyākhyārahojapasamādhaya āpavargyāḥ | prāyaḥ paraṃ puruṣa te tvajitendriyāṇāṃ vārtā bhavantyuta na vātra tu dāmbhikānām
SB 7.9.46