Chapter 9 (Navam Adhaya) is Raj- Vidya Raj-Guhya Yoga.
Sri Krishna tells Arjuna that the knowledge He is going to share with him is easy to attain and simple to practice.
This, The greatest of all knowledge (Raj-Vidya) and the most secret one (Raj-Guhya), knowing which the person becomes free of all bondages and miseries of this aggrieving world.
In the verse 34, Chapter 9 of Srimad Bhagvad Gita, Sri Krishna says:
मन्मना भव मद्भक्तो मद्याजी मां नमस्कुरु ।
मामेवैष्यसि युक्त्वैवमात्मानं मत्परायणः ॥९- ३४॥
manmanā bhava madbhakto madyājī māṁ namaskuru
mām evaiṣ yasi yuktvaivam ātmānaṁ matparāyaṇaḥ 9.34
Manmanā = Always keeping Me in your mind; bhava = become; madbhakta = My devotee; [and]
madyājī = My worshipper, namaskuru = Pay obeisance; mām = to Me.
Yuktvā = Absorbed in; [Me and] matparāyaṇaḥ = holding Me as the Supreme Refuge;
eṣyasi = you would attain; eva= truly;
Always keep your mind engaged in Me, become My devotee, Worship Me and pay obeisance to Me.
By doing this kind of absolute surrendering and taking supreme refuge in Me, you would truly attain Me
There has been a saint named Ras Khan who had supreme devotion for Sri Krishna.
His supreme love for Sri Krisna is seen in his creation of Dohas (couplets), padawalis and savayas.
In one of his padawalis, he has described the way how to keep our mind always engaged in Sri Krishna
सुनिये सब की कहिये न कछू, रहिये इमिया भव वागर में।
करिये व्रत नेम सचाई लिये जेहि सों तरिये भवसागर में॥
मिलिये सब सों दुरभाव बिना रहिये सतसंग उजागर में।
‘रसखान’ गोविन्द को यों भजिये जिमि नागरि को चित गागरि में॥
Listen to everyone, but remain quite, don’t speak anything. In this manner, live in this world.
Perform all your vows and practices with sincerity—they will carry you across this worldly ocean of existence.
Meet everyone without malice or bad feelings, and remain in the association of saints and truth
Rasakhan says, „Worship Govinda and keep Him in your mind the way a village woman balances a water pot upon her head.“
Though the woman carrying pot is talking, laughing with her companions on the way but her mind is always fixed on the pot on her head so that it should not fall down.
We can also do our routine activities living in this world but endeavor not to miss for a moment the engagement of our mind in Sri Krishna.
Always remember the technique of the water pot of the lady….Govind will never go out of your mind…