Bhagavad Gita

ತಸ್ಮಾದ್ ಯಸ್ಯ ಮಹಾಬಾಹೋ ನಿಗೃಹೀತಾನಿ ಸರ್ವಶಃ ।
ಇಂದ್ರಿಯಾಣೀಂದ್ರಿಯಾರ್ಥೇಭ್ಯಸ್ತಸ್ಯ ಪ್ರಜ್ಞಾ ಪ್ರತಿಷ್ಠಿತಾ ॥೬೮॥
tasmād yasya mahābāho nigṛhītāni sarvaśaḥ |
iṃdriyāṇīṃdriyārthebhyastasya prajñā pratiṣṭhitā ||68||

Gist of the sloka:
O Mahavira, such person whose senses are in control and has overcome the sensual objects, will have the truth clearly known.
Lord Krishna says, the mind which is attracted by the outside worldly objects, goes behind them. Without controlling the senses it’s difficult to control the mind. We should therefore train the senses. If it’s all the more important that we train the children at the young age to the right and wrongs. Once the child has obtained fascinations about the wrongs it’s very difficult to lead them back to right path. With no such moral education available to the present children at the home or at school, the entire generation is growing up without this knowledge.
If the child has been trained since young age with the right knowledge and ability to control impulses/senses, then the mind is naturally trained and Dhyana would be easy. So, would assimilation of the true knowledge and realization.
After describing the state of mind and its working, Lord now goes ahead to answer the original question of Arjuna as to how to recognize, a person who has achieved stitha-pragna.