From the Bhagavad Gita

अर्जुन उवाच ।

Arjuna said:

स्थितप्रज्ञस्य का भाषा समाधिस्थस्य केशव । स्थितधीः किं प्रभाषेत किमासीत व्रजेत किम् ॥ २-५४॥

Arjuna asked: O Kesava, what are the characteristics of one who is established in wisdom? How does one with a steady intellect speak? How does one with steady wisdom sit? How does one with steady wisdom walk?

    श्रीभगवानुवाच ।

The Supreme Lord said:

प्रजहाति यदा कामान्सर्वान्पार्थ मनोगतान् । आत्मन्येवात्मना तुष्टः स्थितप्रज्ञस्तदोच्यते ॥ २-५५॥

When one completely renounces all desires that arise in the mind, O Partha, and is satisfied in the self by the self, such a person is said to be firmly established in wisdom.

दुःखेष्वनुद्विग्नमनाः सुखेषु विगतस्पृहः । वीतरागभयक्रोधः स्थितधीर्मुनिरुच्यते ॥ २-५६॥

One whose mind is unperturbed by sorrow, who remains detached in happiness, who is free from longing, fear, and anger, such a person is called a sage of steady wisdom.

यः सर्वत्रानभिस्नेहस्तत्तत्प्राप्य शुभाशुभम् । नाभिनन्दति न द्वेष्टि तस्य प्रज्ञा प्रतिष्ठिता ॥ २-५७॥

One who remains unattached to all objects, whether they are favorable or unfavorable, neither rejoicing nor resenting, such a person's wisdom is firmly established.

यदा संहरते चायं कूर्मोऽङ्गानीव सर्वशः । इन्द्रियाणीन्द्रियार्थेभ्यस्तस्य प्रज्ञा प्रतिष्ठिता ॥ २-५८॥ When one can withdraw the senses from their objects, just as a tortoise withdraws its limbs into its shell, such a person's wisdom is firmly established.

विषया विनिवर्तन्ते निराहारस्य देहिनः । रसवर्जं रसोऽप्यस्य परं दृष्ट्वा निवर्तते ॥ २-५९॥

The objects of the senses turn away from the abstinent person, but the taste for them remains. Even the taste also ceases to exist for one who has realized the Supreme.

यततो ह्यपि कौन्तेय पुरुषस्य विपश्चितः । इन्द्रियाणि प्रमाथीनि हरन्ति प्रसभं मनः ॥ २-६०॥

For the one who is striving, O Arjuna, the senses are turbulent and forcibly carry away the mind, even of a wise person.

तानि सर्वाणि संयम्य युक्त आसीत मत्परः । वशे हि यस्येन्द्रियाणि तस्य प्रज्ञा प्रतिष्ठिता ॥ २-६१॥

But one who controls the senses, keeping them under control and focused on Me, such a person's wisdom is firmly established.

ध्यायतो विषयान्पुंसः सङ्गस्तेषूपजायते । सङ्गात्सञ्जायते कामः कामात्क्रोधोऽभिजायते ॥ २-६२॥

When a person dwells on the objects of the senses, attachment to them arises. From attachment, desire is born, and from desire, anger arises.

क्रोधाद्भवति सम्मोहः सम्मोहात्स्मृतिविभ्रमः । स्मृतिभ्रंशाद् बुद्धिनाशो बुद्धिनाशात्प्रणश्यति ॥ २-६३॥

From anger, delusion arises, and from delusion, the loss of memory. With the loss of memory, intelligence is destroyed, and with the destruction of intelligence, one perishes.

रागद्वेषविमुक्तैस्तु विषयानिन्द्रियैश्चरन् । orवियुक्तैस्तु आत्मवश्यैर्विधेयात्मा प्रसादमधिगच्छति ॥ २-६४॥

But those who are free from attachment and aversion, who control their senses with determination, and who are self-disciplined, such individuals attain tranquility and the grace of the divine.

प्रसादे सर्वदुःखानां हानिरस्योपजायते । प्रसन्नचेतसो ह्याशु बुद्धिः पर्यवतिष्ठते ॥ २-६५॥

With the attainment of tranquility, all the sorrows are destroyed, and the intellect of one whose mind is serene becomes steady and focused.

नास्ति बुद्धिरयुक्तस्य न चायुक्तस्य भावना । न चाभावयतः शान्तिरशान्तस्य कुतः सुखम् ॥ २-६६॥