Sri Ramanuja's Sanskrit Commentary
(English Translation  by Dr. S Sankaranarayan

The mature stage of Yoga

Bhagavad Gita Chapter VI Slokas 29-32

6.28 Thus, in the above-said manner, devoting himself to the Yoga of the self and by that means expelling all old impurities, the Yogin attains 'perfect', i.e., boundless felicity at all times easily, without stress and strain. The felicity is born of the contact with the Brahman (Atman), meaning the joy of experience of the Brahman. Now Sri Krsna says that the mature stage of Yoga consists of four degrees, as stated in the succeeding verses from 29th to 32nd.

6.29 (i) On account of the similarity between one-self and other selves when They are separated from Prakrti (i.e., the body), all selves are by Themselves only of the nature of knowledge. Inequalities pertain only to Prakrti or the bodies they are embodied in. One whose mind is fixed in Yoga has the experience of the sameness of the nature of all the selves as centres of intelligence, the perceived difference being caused only by the body. When separated from the body all are alike because of their being forms of centres of intelligence. An enlightened Yogin therefore sees himself as abiding in all beings and all beings abiding in his self in the sense that he sees the similarity of the selves in himself and in every being. When one self is visualised, all selves become visulaised, because of the similarity of all selves. This is supported by the statements: 'He sees sameness everywhere' (6.29). The same is again referred to in, 'This Yoga of equality which has been declared by you' (6.33), and the statement 'The Brahman when uncontaminated is the same everywhere' (5.19).

6.30 (ii) He who, having reached the highest stage of maturity, views similarity of nature with Me, i.e., sees similarity of all selves to Myself when They are freed from good and evil and when they remain in Their own essence, as declared in the Sruti, 'Stainless he attains supreme degree of equality' (Mun. U., 3.1.3); and 'sees Me in all selves and sees all selves in Me.' That is, on viewing one of Them (selves), one views another also to be the same, because of their similarity to one another. To him who perceives the nature of his own self, I am not lost on account of My similarity to him i.e., I do not become invisible to him. He (the Yogin) viewing his own self as similar to Me, always remains within My sight when I am viewing Myself, because of similarity of his self with Me. Sri Krsna describes a still more mature steps (of Yoga):

6.31 (iii) The Yogin who, fixed in the state of Yoga in oneness because he has the same form of uncontracted knowledge (as Myself), worships Me steadfastly by renouncing the differences of the Prakrti (i.e., of the body) --- then that Yogin, even while coming out of Yoga, howsoever he may live, views Me only, when viewing his own self and all other beings. The meaning is that he views his similarity to Myself in his own self and in the self of all beings. Now Sri Krsna proceeds to speak of the maturest stage beyond this:

6.32 (iv) He who --- because of the similarity between his own self and other selves, as they are all constituted similarly of uncontracted knowledge in their essential being --- views the pleasures in the form of the birth of a son and the sorrows in the form of the death of a son of his own and of others, as equal, on the ground of their equal unrelatedness to such pleasures and pains to him. Viewing his own pleasures and pains of the above description as being not different from those of others of the same kind --- tht Yogin is deemed the highest; he is judged as having reached the summit of Yoga.
[The idea is to prevent misconstruing the verse as meaning that one shares the joy and misery of all as his own. It means only that the highest type of yogins understand that the self is unrelated to the pain and pleasures of his own body-mind. He understands also that the same is the case with other selves.]

Sri Sankaracharya's Sanskrit Commentary on Sloka 6-30
English Translation  by Swami Gambhirananda

Yah, one who   pashyati, sees   maam, Me (Vasudeva), who am the Self of all    sarvatra, in all things
, and sees   sarvam, all things, all created things, beginning from Brahma   mayi, in Me who am the Self of all-
, I (who am God)  na pranasyami, do not go out  tasya, of his vision, of one who has thus realized the unity of the Self
ca sah
, and he also    na pranasyati, is not lost to me, to My vision.

That man of realization does not get lost to Me, (Vasudeva),
because of the indentity between him and Me;
for that which is called one's own Self is surely dear to one,
and it is I alone who am the seer of the unity of the Self in all.