Srimad BhagavadGita

This śloka conveys the gist of the 2nd chapter and states that one who has faith in performing Karma yoga -'Action without attachment' is sure to attain soul realisation.

Kṛṣṇa says to Arjuna, "O Arjuna! Attaining true knowledge about the soul and remaining firmly established in performing actions without attachment (sanga rahita karma), leads to the attainment of the soul, also called as 'brahmam'. Having attained this state of perfection in performing actions without attachment, he does not fall prey to delusion. By remaining firmly established in this state of karma yoga even at the hour of death, he attains the blissful soul."

eṣā sthitiḥ (The state talked about in this chapter) Since this chapter primarily talks about karma yoga, it is apt to interpret the meaning of the words 'sthitiḥ' here as 'the state of being firmly established in karma yoga'. The word 'eṣā' sums up all the processes described so far in this chapter, hence it refers to the dedicated practice of karma yoga which results in the steady execution of karmas without any attachment, serving as means for achieving the state in jñāna yoga called sthitaprajñātva which results in attainment of the soul.

Brāhmī (That leads to attainment of brahmam) This word brāhmī can have two likely meanings.

1)Brāhmī- That leads to attainment of brahmam 'The Supreme Soul'.

This karma yoga leads to jñāna yoga and bhakti yoga and ultimately the attainment of Parabrahma (Supreme soul). The earlier ślokas like sarva duḥkhānāṃ...BG 2.65 also talk about the ultimate purpose being the attainment of the Supreme Soul which results in complete freedom from the bondage of saṃsāra. 

2)Brāhmī- That leads to the attainment of brahmam 'The Soul'.

Since the commentary says that the word brahma in the second line of the śloka refers to the soul, the word Brāhmī here can also be understood to mean that, 'This karma yoga leads to the attainment of the soul'. Karma yoga results in a steady mind where knowledge about the soul manifests and sthitaprajñā state is achieved which results in soul realisation.

enāṃ prāpya (Upon attaining steady perfection in karma yoga with its attributes as mentioned earlier)

na vimuhyati (One does not fall prey to delusions like assuming the body to be the soul, resulting in further bondage with the saṃsāra)

asyām antakāle'pi sthitva (Even in the last stage of his lifetime if he attains this steady perfection in karma yoga) Since it is not possible to achieve steady perfection in karma yoga at the time when the soul is about to leave the body, 'antakāle' here means the last phase of one’s lifetime.

As told in the Bodhāyana sūtra uttame cīdvayasi sādhuvṛttaḥ (if he has good conduct in his last days), here the word api conveys that even a person who might have indulged in the sense objects in his boyhood and youth, if he repents later and enters the path of karma yoga, he is eligible for this reward of karma yoga. With this, it is certain by kiṃ punar nyāya (which is very obvious) that one who is steadily established in karma yoga since his early student phase is sure to attain its reward. 'asyām sthitva' means 'when one is steadily established in karma yoga'.

nirvāṇam brahma ṛcchati (Attains the soul which is bliss personified) Karma yoga practised with jñāna yoga as the goal leads to the attainment of the soul. It is therefore apt to take the meaning of brahma to be the soul here. 

Nirvāṇam From kāyo vāṇaṃ śarīraṃ ca, we know that 'vāṇa' means the body. Therefore the word

nirvāṇam means the blissful soul separated from the body.

Chapter Summary:

Arjuna lacked Knowledge about the original nature of the soul and was unaware of the fact that fighting the war serves as a means to mokṣa for a kṣatriya. He assumed the body itself to be the soul and was thus struck by fear and grief. Unable to bear the grief, Arjuna declared that he will not fight the war. In order to bring Arjuna out of his deluded state and give him clarity, in this chapter, Kṛṣṇa started with the description of the actual knowledge about the eternal soul first. This was followed by a description of the practice of karma yoga endowed with soul knowledge, which involves the execution of varṇa āśrama karmas like fighting the war, etc, without any attachment to their rewards. Kṛṣṇa instructed further that diligent practice of karma yoga bestows the sthitaprajña state (jñāna yoga) which leads to the realisation of the soul. This sequence was described by Kṛṣṇa in Chapter 2. The same has been stated by Sri Ālavandār in his Gītārtha saṃgraham śloka 6 as

nityātmāsaṃgakarmehagocarā sāṃkhyayogadhīḥ | dvitīye sthitadhīlakṣā proktā tanmohaśāntaye (Knowledge about the soul and knowledge about karma yoga which have the eternal soul entity and execution of actions without attachment as their subject matters, are explained by Kṛṣṇa in the second chapter to clear Arjuna's delusion).