Next verse is summing up sannyāsa as yoga/means in terms of lifestyle, called vividisā-sannyāsa.
sarvadharmān parityajya māmekaṁ śaraṇaṁ vraja । ahaṁ tvā sarvapāpebhyo mokṣayiṣyāmi mā śucaḥ ॥18-66॥
Giving up all karmas, take refuge in Me alone. I will release you from all karmas; do not grieve.
This is considered to be the last verse of teaching in the Gītā. The teaching of Gītā begins with the statement, “you are grieving over what does not deserve to be grieved for,” Gītā 2.11, and it ends here with, “do not grieve.” Therefore, it is clear that the whole purpose of the Gītā is to remove sorrow.
When it is said that dharma should be given up - sarvadharmān parityajya, here includes both dharma and adharma, which is karma. Giving up karma is denoting vividisā-sannyāsa, since the practice of dharma and adharma is only in terms of karma. When dharma, artha, and kāma are not the ends, naturally karma to attain them have no purpose and are given up. If they are the ends, karma can never be given up because dharma, artha and kāma can be gained only by karma. Therefore the qualified one is asked to give up both actions (dharma and adharma) and take refuge only in Īśvara - māmekaṁ śaraṇaṁ vraja, through sannyāsa, one pursues only ātmā-jñānam, and be free.
idaṁ te nātapaskāya nābhaktāya kadācana । na cāśuśrūṣave vācyaṁ na ca māṁ yo'bhyasūyati ॥18-67॥
This (teaching which has been taught) to you is never to be taught to the one who has no religious discipline, nor to the one who has no devotion, nor to the one who is not willing to listen, nor to the one who finds fault with me (where there is none).
This - idaṁ, here refers to the Gītā-śāstra beginning with “you are grieving for no reason,” and ending with “do not grieve.” It has been taught to you - te, and is not to be taught - na vācyaṁ to certain people. To whom should it not be given? atapaskāya - to the person who has no religious discipline, which would include those who have no intellectual discipline - amedhāvī. These are generally said together. Tapas is also considered to be knowledge or the pursuit of knowledge. As Bhrgu is told by his father in the Taittirīyopanisad, “by tapas, may you understand Brahman - tapasā brahma vijiñāsasva.” There, tapas is purely enquiry. But here we can say that the one who has tapas has commitment and is ready to put forth effort for a disciplined life in order to equip himself for this knowledge. To the one who does not have this, atapaskāya, it is not to be given.
Further, this teaching should not be given to the one who has no devotion - abhaktāya. This devotion should be for both the teacher and Īśvara. That means śraddhā and certain awareness of Īśvara is necessary to be there. This devotee appreciates the necessity of invoking Īśvara’s grace for moksa. Here, the devotee is necessarily the jijñāsu-bhakta. As he has devotion to Parameśvara, he also has commitment to the teacher and the teaching.
Then again, it should not be told to the one who has no desire to listen - aśuśrūṣave. And there is a rule for the teacher that he should not teach unless this knowledge is specifically asked for. To whom else should this not be given? It should not be given to one who finds fault with the Gītā or Krsna. One may look upon Krsna as arrogant, for instance, because he says “there is no other than or superior to me,” Gītā 7.7, and “salute me,” Gĩtā 18.65.
There are many more expressions like this in Gītā. If a person uses the first person too much, people can think that he is arrogant. But here, Krsna talks as Īśvara, and if he is viewed as Īśvara, the teaching becomes effective. A person who is abhyasūyati - find fault, is not to be taught, because, with such an attitude, the teaching will not be fruitful.
Now, when one teaches following the tradition - sampradāya, what is the result for that teacher?
ya imaṁ paramaṁ guhyaṁ madbhakteṣvabhidhāsyati । bhaktiṁ mayi parāṁ kṛtvā māmevaiṣyatyasaṁśayaḥ ॥ 18-68॥
The one who teaches this most exalted secret (śāstra) to my devotees, having the highest devotion for Me, will come to me alone. There is no doubt.
yaḥ abhidhāsyati - the one who teaches, this applies not only to Arjuna, but to whomever one teaches this śāstra. This śāstra is considered the most exalted - paramaṁ, because understanding its subject matter will give moksa. And this teaching, which is in the form of a dialogue between Krsna and Arjuna is most secret - guhyaṁ. Why is it to be kept secret? Because it may damage the person who is not ready for it. A simple devotee, if he is told that he is Bhagavān, he may give up his devotion, and may not gain knowledge and be worse off than he was before being exposed to this teaching. Thus, this knowledge must be taught only to the person who is ready for it. Therefore it is a secret.
To whom is the teaching given? To my devotee - madbhakteṣu. Generally devotees are committed to security - artha and pleasure - kāma, and take the Lord’s help to achieve those ends. But here, the devotees want the knowledge of Parameśvara.They are jijñāsu and their only goal is moksa. Then Lord Krsna says here that the one who is teaching this knowledge is doing the highest form of devotion to Me - bhaktiṁ mayi parāṁ. When the person is teaching, he is revealing Bhagavān, and that is his service to the Lord. To do that he has to understand Bhagavān, and he reaches me alone - mām eva eṣyati, either he is a jñānī or he gains nisthā by teaching.
na ca tasmānmanuṣyeṣu kaścinme priyakṛttamaḥ । bhavitā na ca me tasmād anyaḥ priyataro bhuvi ॥ 18-69॥
And there is no one other than him who is the best among men who do what is dear to me, and there will not be another dearer to me on the earth than he.
Among all devotees, jñānī is the dearest to Bhagavān. Why? Because the one who knows me is myself. The self is the most beloved, its nature being limitlessness which is happiness. That is the object of anybody’s love. The person who knows ātmā is teaching ānanda-svarūpa and he is not separate from ānanda-svarūpa.