Sanskrit text in Devanagari, Kannada, Gujarati, English , Telugu
||om tat sat||
śrī bhagavānuvāca:
idaṁ tu tē guhyatamaṁ pravakṣyāmyanasūyavē|
jñānaṁ vijñānasahitaṁ yat jñātvā mōkṣyasē'śubhāt||
"I will tell this highest secret to you , the one who has gone beyond petty jealousies. That is the knowledge embedded with experience, knowing which you will be free from all evil !".

bhagavadgīta
navamādhyāyaḥ
rāja vidyā rājaguhya yōgaḥ

Krishna begins the ninth chapter telling Arjuna, the secret knowledge knowing which he will be free from evil (attain liberation).

This sounds like a familiar refrain.

In the seventh chapter also Krishna starts by saying '..since you have interest in Me ( Brahman), I will tell you how you may know Me fully'. "asaṁśayaṁ samagraṁ māṁ yathā jñāsyasi tat śr̥ṇu" , emphasizing that one will know him without any doubt and fully. He promises that, he will teach that knowledge, "knowing which there nothing else that is worth knowing".

Then Krishna starts by telling about the nature of Brahman.
The "aparā", inferior component, which consists of ( bhūmi rāpō nalō vāyu..) " and the superior "parā". The "parā" is the basis of all living beings. parā and aparā are responsible for all the sentient and insentient beings.

Elaborating the all pervasiveness of Brahman, Krishna tells Arjuna that Brahman is the seed in all beings.

That nature of Brahman is not known to all because of ignorance and Maya. Only those who are able to overcome the ignorance are able to perceive the Brahman and attain the liberation (Moksha). Liberation is the realization of Brahman as none other than the self as well as the actions performed without wanting the enjoyment of fruits.

Further elaborating the nature of Brahman Krishna says that those who realize him as existing as part of everything 'Adhibhuta Adhidaivam Adhiyagnya' etc such people are able to remember him even in their last moments. This sets off Arjuna asking more questions as to what are Adhibhuta Adhidaivam Adhiyagnya etc. Krishna clears all the doubts of Arjuna, through the major part of eighth chapter. Even as he was doing that Krishna also elaborates on how one who can block all paths in the body through yoga, focusing on the place between the two eyes. And if such a one lets the vital force (Prana) leave the body while uttering the syllable "om", then he will attain Moksha. But this may be an arduous task beyond all but a few. So Krishna also elaborates an easier way too.

But at the end of the eighth chapter one may be perplexed by the thoughts of having to remember the almighty and utter "om" in those ultimate moments as a way to attain Moksha.

As though to answer that fear Krishna starts the ninth chapter with a promise, just as he did in the seventh chapter. The promise is to tell that knowing which one will be free from all evil .

That is Raja vidya Raja guhya Yoga.

Raja Vidya is that Vidya or the "knowledge taught" that is most valuable. That most valuable knowledge rāja vidyā" is none other than the knowledge of Brahman. It is also a secret by virtue of it not being known to many.

That is the topic of this chapter nine titled "Rajavidya Rajaguhya Yoga"

śrī bhagavānuvāca:
idaṁ tu tē guhyatamaṁ pravakṣyāmyanasūyavē|
jñānaṁ vijñānasahitaṁ yat jñātvā mōkṣyasē'śubhāt||1||

Krishna is telling Arjuna about the knowledge of Brahman. It is most important knowledge. It is auspicious. It is knowledge of righteous activities. It is easy to follow. It is imperishable. This is for one who is beyond jealousies etc and has a clear mind.(9.02)

People without diligence unable to obtain the knowledge of Self are forever lost in this life busy, earning merits and demerits.(9.03)

Talking about the Supreme nature of Brahman, Krishna elaborates saying that the whole universe is pervaded by the unmanifest form of Brahman. All beings are established in the Brahman with Brahman as the support. Brahman is not dependent on them( matthsāni sarva bhūtāni na cāhaṁ tēṣvavasthitaḥ) (9.04)

Like the wind which is present in space, all beings are in the Brahman (9.06)

All beings merge into Brahman at the end of the cycle only to be created again at the start of the cycle.(9.07)

The beings lost in this cycle ( being in pursuit of merits and demerits etc) are thus not independent beings ( ever bonded pursuing actions of fruit). So they get created again and again.( 9.08)

What are the foolhardy ones doing, "paraṁ bhāvaṁ ajānaṁtō- not knowing the supreme nature "?
The ignorant not knowing the Supreme nature, not realizing the oneness of the Paramatman and the Self ( Jivatma), they are disregarding the Self which is occupying this body.

Who are the foolhardy ones ?
mōghāśā - people with vain hopes
mōghakarmāṇō - people busy with vain actions
mōghajñānā- people with vain knowledge
vicētasaḥ - people without the discriminating power
asurīṁ prakr̥tiṁ śritāḥ- the people who follow the ways of Asuras ( who believe the body is the self)

All of these ( meaning the above who follow the ways of Asuras etc) disregard the Self.(9.12)

Those who do not disregard the Self are the ones who follow the divine nature know him as the imperishable source of all beings and worship Him (9.13)

How do they worship him?
Krishna elaborates on how the people of divine nature worship:
śrībhagavānuvāca
satataṁ kīrtayantō māṁ yatantaśca dr̥ḍhavratāḥ |
namasyantaśca māṁ bhaktyā nityayuktā upāsatē||14||
jñānayajñēna cāpyanyē yajantō māmupāsatē|
ēkatvēna pr̥thaktvēna bahudhā viśvatō mukham||15||

The ones who follow the divine nature they are "Always glorifying me, and always striving , paying obeisance with single minded devotion"
Some of them worship with the knowledge of One ( ēkatvēna)
Some worship with the Supreme one in different forms ( pr̥thaktvēna).
Some worship me as the Supreme one who is multiformed ( viśvamukham)

Krishna, having said that they worship Me, goes on to elaborate on the form of the Supreme one in four slokas

śrībhagavānuvāca
ahaṁ kratuḥ ahaṁ yajñaḥ svadhāhamahamauṣadham|
mantrō'hamahamēvājyaṁ ahamagnirahaṁ hutam||16||
pitā'hamasya jagatō mātā dhātā pitāmahaḥ |
vēdyaṁ pavitramōṁkāra r̥ksāmayajurēvaca ||17||
gatirbhartā prabhussākṣī nivāsaśśaraṇaṁ suhr̥t|
prabhavaḥ praḷayaḥ sthānaṁ nidhānaṁ bījamavyayam||18||
tapāmyahamahaṁ varṣaṁ varṣaṁ nigr̥hṇāmyutsr̥jāmi ca|
amr̥taṁ caiva mtyuśca sadasaccāhamarjuna||19||

Meaning there by that " I am the kratu. I am the Yajnya. I am aushadha. I am the mantra. I am the aujya. I am the fire. I am the act of offering. Of this world I am the father, I am the mother I am the grandfather too. I am the knowable, I am the sanctifier, I am also "om", I am the Rk etc I am the fruit of action, the Lord , the witness, abode , refuge, friend , the origin , the end, foundation, the imperishable seed. I give heat, I give and withhold rain. I am the nectar and also death. I am the existence and nonexistence too."

That is the form of the Supreme one. Because of ignorance, people are not able to realize the same.

Those who have studied the three Vedas , who have had the drink of Soma, those who have got rid of sins too perform Yagnyas and pray to the God and ask for the heaven as a fruit. They obtain the same. Once their merits have been used up, they take rebirth. Thus they obtain what they wished for and remain in the cycle of birth and death. (9.20,21)

Then how to get out of this cycle ?.

Krishna tells the way.
śrībhagavānuvāca:
ananyāścintayantō māṁ ē janāḥ paryupāsatē |
tēṣāṁ nityābhiyuktānāṁ yōgakṣēmaṁ vahāmyaham||22||

This is a solemn assurance and worth repeating to ourselves !
ananyāḥ cintayantō - without thinking of any other
ē janāḥ - those people
paryupāsatē - (who) meditate ( on Me)
nityābhiyuktānāṁ- being attached to Me
yōgakṣēmaṁ - (their) welfare ( is ensured)

Meaning that:
" The persons who without thinking of any other form meditate on Me, their welfare preserving what they have and securing what they need is ensured by Me "

This is indeed a solemn assurance.
It is a guarantee!

There is no need for the strict process of Yoga detailed in akṣarapara brahmayōga. Though it was clarified there itself ( tasyāhaṁ sulabhaḥ pārtha "I am easily available for them"), this solemn assurance removes all doubts if any.

Krishna tells one more thing.
śrībhagavānuvāca:
yē'pyannya dēvatā bhaktā yajantē śraddhayānvitaḥ |
tē'pi māmēva kauntēya yajantya vidhipūrvakam||23||

meaning that
" Even those, who being devoted to other deities and endowed with faith worship them, also worship Me alone though following a different path".

Having said "ahaṁ kratuḥ ahaṁ yajñaḥ", Krishna clarified that though they may worship other gods they are actually worshipping him . Those who worship other forms not knowing the Brahman attain that form which they worship. They may not be attaining the birthless state, depending on the choices they made. Again emphasizing that prayer without focusing on any other goals is the only way.(9.25)

Emphasizing the simplicity of worship as opposed to Yagnyas Krishna says the following:

śrībhagavānuvāca
patraṁ puṣpaṁ phalaṁ tōyaṁ yōmē bhaktyā prayacchati|
tadahaṁ bhaktyupahr̥tamaśnāmi prayatātmanaḥ||26||

"Whoever offers me with devotion a leaf, a flower, or a fruit, or water, I accept that gift of that pure hearted man which has been devotionally presented".

Not only that Krishna gives one more piece of advice.

"Oh Arjuna whatever you do, whatever you eat, whatever you offer as a sacrifice, whatever you give, whatever austerities you undertake, all of that you offer to Me (the Supreme being)"(9.27) . Such offering frees one from the bondage of action. It becomes an act of selfless action (9.28). That was also the path of Karma yogi, as taught in karma Yoga.

"yē bhajanti tu māṁ bhaktyā mayi tē tēṣu cāpyaham||"(9.29)

In this worship of God there are no levels. Those who worship him with devotion they are in "Him" and "He" is in them.

The solemn promise of "ananyāściṁtayaṁtō māṁ" is applicable to all.

To restate the same Krishna goes to other extreme of a person with bad character. If he worships "Him", his sins melt away and they become people who attain liberation. So the solemn promise is applicable to all.

Krishna says:
"striyō vaiśyāstathā śudrāstē'pi yānti parāṁgatim||"
" Women, Vaishyas, Sudras can also attain Moksha "

Hence Krishna says to all of the worshippers :

śrībhagavānuvāca:
manmanābhava madbhaktō madyājīmāṁ namaskuru|
māmēvaiṣyasi yuktvaiva mātmānaṁ matparāyaṇaḥ||34||

Meaning,
manmanāḥ - with a mind fixed on Me
madbhaktaḥ - being devoted to Me
madyājī- worshipping Me
māṁ namaskuru - bow down to Me
ātmānaṁ yuktvaiva - concentrating your mind on Me
matparāyaṇaḥ - Accepting Me ( as the Supreme goal)
mām ēṣyasi - you will attain Me !!

"Having your mind fixed on Me, be devoted to Me, worshipping Me, bow down to Me,. By concentrating and accepting me as the Supreme goal you will surely attain me "

This is Rajavidya, the best knowledge.
This is Rajaguhya the highest secret .

The difficult paths for attaining Moksha are known.
They have been detailed too.
But an easier path has been enunciated by Krishna saying "ananyāḥ ciṁtayaṁtō māṁ "

That path detailed by Krishna is the secret path for Liberation
That is the Rajavidya Rajaguhya Yoga.
||ōm tat sat||
śrībhagavānuvāca:
manmanābhava madbhaktō madyājīmāṁ namaskuru|
māmēvaiṣyasi yuktvaiva mātmānaṁ matparāyaṇaḥ||
"Having your mind fixed on me, be devoted to me sacrifice to me, bow down to me. By concentrating and accepting me as the Supreme goal you will surely attain me "
||om tat sat||