Verse
असंयतात्मना योगो दुष्प्राप इति मे मतिः ।वश्यात्मना तु यतता शक्योऽवाप्तुमुपायतः ॥
asaṃyatātmanā yogo duṣprāpa iti me matiḥvaśyātmanā tu yatatā śakyo’vāptumupāyataḥ
By one who is not self-controlled, this Yoga is difficult to attain; but by the self-controlled, it is attainable by properly directed efforts.
Gītā 6·36