Bhagavad Gita: Chapter 8, Verse 8

अभ्यासयोगयुक्तेन चेतसा नान्यगामिना |
परमं पुरुषं दिव्यं याति पार्थानुचिन्तयन् || 8||

abhyāsa-yoga-yuktena chetasā nānya-gāminā
paramaṁ puruṣhaṁ divyaṁ yāti pārthānuchintayan

abhyāsa-yogaby practice of yog; yuktenabeing constantly engaged in remembrance; chetasāby the mind; na anya-gāmināwithout deviating; paramam puruṣhamthe Supreme Divine Personality; divyamdivine; yātione attains; pārthaArjun, the son of Pritha; anuchintayanconstant remembrance


BG 8.8: With practice, O Parth, when you constantly engage the mind in remembering Me, the Supreme Divine Personality, without deviating, you will certainly attain Me.


This instruction to keep the mind always engaged in meditating upon God has been repeated numerous times in the Bhagavad Gita.  Here are a few verses:

ananya-chetāḥ satataṁ   8.14

mayyeva mana ādhatsva   12.8

teṣhāṁ satata-yuktānāṁ   10.10

The word abhyāsa means practice—the training and habituating of the mind to meditate upon God.  Such practice is to be done, not at fixed times of the day at regular intervals, but continuously, along with all the daily activities of life.   

When the mind is attached to God, it will get purified, even while performing worldly duties.  It is important to remember that what we think with our mind fashions our future, not the actions we perform with our body.  It is the mind that is to be engaged in devotion, and it is the mind that is to be surrendered to God.  And when the absorption of the consciousness in God is complete, one will receive the divine grace.  By God’s grace, one will attain liberation from material bondage, and will receive the unlimited divine bliss, divine knowledge, and divine love of God.  Such a soul will become God-realized in this body itself, and upon leaving the body, will go to the Abode of God.