We have taken too long with the 9th chapter, but it is appropriate because it is rājavidyārājaguhya-yogaḥ, it is the chapter which deals with the supreme Knowledge, rājavidya, the royal knowledge and that rājaguhya, the supreme secret, what is called ‘secret of secrets’ and as we found out, the verses n°4&5, which are the most difficult verses of the Bhagavad Gita which require a lot of elucidation and this chapter also gives you a synthesis of three Yogas: Karmayoga, Bhaktiyoga and Jnanayoga. So, this one chapter gives you integral knowledge of the integral divine and gives you an integral path to attain to the integral knowledge and the integral divine. So, you might say this is the summit, the summit of the entire teaching and that is why this entire chapter deserved to be dealt with in such an elaborated manner.
You will see also in the 10th chapter again there is a summary of the 9th chapter. Because Sri Krishna will tell Arjuna that ‘I shall tell you once again the supreme word, the word which has been explained in the 9th chapter in order to make sure to Arjuna that that knowledge is precisely sized by the mind of Arjuna to make it sure He says, ‘bhūyaḥ ṣṛṇu me vacaḥ, ‘Once again you listen to that word’; so, once again in the 10th chapter there is a summary of the summary of the 9th chapter. But let us still continue with the 9th chapter because we had only done the first 5 verses of the 9th chapter. The other verses of this chapter are not very difficult, but you will wee in the rest of the verses an elucidation of the three Yogas: the statement of the integral knowledge and then the statement of the three Yogas: Karmayoga, Bhaktiyoga and Jnanayoga. But these three Yogas are given in such a way that they can be integrated. And there is a greater emphasis upon the unity of Jnana and Bhakti. The reason is that the union of Karma and Jnana, (action and knowledge) was already expounded fully in the first 6 chapters. The union of action and knowledge was the theme of the first 6 chapters. From chapter n°7 to 12, the theme is of the union of knowledge and devotion as continued with the union of action and knowledge. That is why in this chapter particularly which is a kind of a summit of the Bhagavad Gita you might say, the secret of secrets is given here, rājaguhya is given, the supreme secret is given, there you will find an integration of knowledge, devotion, and action.
Now, with regard with integral knowledge, verses 4&5 which you have given already, which we have studied already, these two verses which are the most difficult verses, elucidate to us the most important elements of integral knowledge: the supra-cosmic, which is not extra-cosmic; the supreme Reality is supra-cosmic, it is transcendental but which is not extra-cosmic, it does not exclude the universe and yet it is more than universe. Because it is more than universe, the Reality, the supreme is supposed to be not contained in the world and yet the whole world is something which is within the Supreme, nothing is outside the Supreme.