2.53

श्रुतिविप्रतिपन्ना ते यदा स्थास्यति निश्चला ।
समाधावचला बुद्धिस्तदा योगमवाप्स्यसि ॥

śrutivipratipannā te yadā sthāsyati niścalā
samādhāv acalā buddhis tadā yogam avāpsyasi

Kṛṣṇa (कृष्ण) is speaking, in the last verse before Arjuna (अर्जुन) asks.

The verse

When your buddhi, pulled about by what you have heard, stands unmoving and unwavering in samādhi (समाधि), then you will reach yoga.

नेपालीमा

जब सुनिएको कुराले तानिएको तिम्रो बुद्धि समाधिमा अचल र नडगमगाउने भएर उभिन्छ, तब तिमी योगमा पुग्छौ।

Where it sits

The stretch that began "hear this in yoga" ends when the buddhi stands still and yoga is obtained, after yoga has been defined as evenness and as skill, and the right has been set on the act. He has not yet said what that man looks like when he speaks, sits, and walks, which is what Arjuna (अर्जुन) asks next.

Split: श्रुति-विप्रतिपन्ना + ते + यदा + स्थास्यति + निश्चला + समाधौ + अचला + बुद्धिः + तदा + योगम् + अवाप्स्यसि

śruti-vipratipannā + te + yadā + sthāsyati + niścalā + samādhau + acalā + buddhiḥ + tadā + yogam + avāpsyasi

Sanskrit, in depth

The words

देवनागरीWordGrammarSense
श्रुति-विप्रतिपन्नाśruti-vipratipannānominative femininepulled in contrary ways by what has been heard.
तेtegenitive encliticyour.
यदाyadāindeclinablewhen.
स्थास्यतिsthāsyatifuture, 3rd singularwill stand.
निश्चलाniścalānominative feminineunmoving.
समाधौsamādhaulocativein samādhi (समाधि).
अचलाacalānominative feminineunwavering.
बुद्धिःbuddhiḥnominativethe buddhi.
तदाtadāindeclinablethen.
योगम्yogamaccusativeyoga.
अवाप्स्यसिavāpsyasifuture, 2nd singularyou will obtain. From ava-āp (अव-आप्).

The phrases

śrutivipratipannā te buddhiḥ (श्रुतिविप्रतिपन्ना ते बुद्धिः) is the subject, split by the verse. Your buddhi, the one that what-you-have-heard has pulled this way and that. The hearing is the śruta (श्रुत) of 2.52 and the vedavāda (वेदवाद) of 2.42. Feminine, because buddhiḥ (बुद्धिः) is feminine. niścalā (निश्चला) and acalā (अचला) agree with it too.

yadā sthāsyati niścalā (यदा स्थास्यति निश्चला) is the when. When it will stand unmoving.

samādhau acalā (समाधौ अचला) is where, and how. Unwavering in samādhi (समाधि). This is the samādhi (समाधि) that 2.44 said the buddhi of resolve is not set in, for the man whose mind the flowered speech has carried off.

तदा योगम् अवाप्स्यसि tadā yogam avāpsyasi is the then. Then you will reach yoga. The yoga is the evenness of 2.48 and the skill of 2.50. The verb is second person. The buddhi stands; you obtain.

Sanskrit in this line

समाधौ + अचला samādhau + acalā is recited samādhāv acalā (समाधावचला). औ + अ au + a becomes āva (आव). The locative ending --au (औ) of samādhi (समाधि) is still the locative after the join. You hear āva (आव), and you split back to au (औ) plus the a (अ) of acalā (अचला). बुद्धिः + तदा buddhiḥ + tadā is buddhis tadā (बुद्धिस्तदा): ḥ (ः) after i (इ), before voiceless t (त्), becomes s (स्).

Say it back

The state of the buddhi when yoga is reached. If niścalā (निश्चला) and acalā (अचला) come out as two different women, stay here. They are the buddhi.