In plain words
That buddhi which knows pravṛtti and nivṛtti, what ought and ought not to be done, fear and fearlessness, bondage and Mokṣa, is sāttvikī, Partha.
Word for word
Which knows pravṛtti and nivṛtti, what is to be done and not done, fear and fearlessness, bondage and mokṣa, that buddhi, O son of Pṛthā, is sāttvikī.
प्रवृत्तिं च निवृत्तिं च कार्याकार्ये भयाभयेबन्धं मोक्षं च या वेत्ति बुद्धिः सा पार्थ सात्त्विकी
Other commentaries
The commentators
▸Bhagavadgītābhāṣyam· bhāṣya
प्रवृत्तिं च प्रवृत्तिः प्रवर्तनं बन्धहेतुः कर्ममार्गः शास्त्रविहितविषयः, निवृत्तिं च निर्वृत्तिः मोक्षहेतुः संन्यासमार्गः — बन्धमोक्षसमानवाक्यत्वात् प्रवृत्तिनिवृत्ती कर्मसंन्यासमार्गौ इति अवगम्यते — कार्याकार्ये विहितप्रतिषिद्धे लौकिके वैदिके वा शास्त्रबुद्धेः कर्तव्याकर्तव्ये करणाकरणे इत्येतत् ; कस्य ? देशकालाद्यपेक्षया दृष्टादृष्टार्थानां कर्मणाम् । भयाभये बिभेति अस्मादिति भयं चोरव्याघ्रादि, न भयं अभयम् , भयं च अभयं च भयाभये, दृष्टादृष्टविषययोः भयाभययोः कारणे इत्यर्थः । बन्धं सहेतुकं मोक्षं च सहेतुकं या वेत्ति विजानाति बुद्धिः, सा पार्थ सात्त्विकी । तत्र ज्ञानं बुद्धेः वृत्तिः ; बुद्धिस्तु वृत्तिमती । धृतिरपि वृत्तिविशेषः एव बुद्धेः ॥ ३० ॥
In plain words
'Engagement' means undertaking, the very cause of bondage — the path of action, covering everything scripture enjoins. 'Withdrawal' means cessation, the cause of liberation — the path of renunciation. Because bondage and liberation appear together in the same sentence, we understand that engagement and withdrawal are exactly these two paths, action and renunciation. 'What is to be done and what is not' means: what is enjoined and what is forbidden, whether in worldly or scriptural matters, as discerned by a scripturally-trained intellect — the same thing meant by 'duty and non-duty', 'doing and not-doing'. Of what, though? Of actions whose purposes are seen and unseen, with reference to time, place, and the like. 'Danger and safety' — 'danger' is that from which one fears, like thieves or tigers; 'safety' is simply the absence of danger; together they are 'danger-and-safety', and what's really meant are their causes, seen and unseen. The intellect that knows bondage together with its cause, and liberation together with its cause — that, Pārtha, is sāttvika. Here, knowledge is simply a function of the intellect; the intellect itself is what possesses such functions. And steadiness, too, is nothing more than one particular function belonging to the intellect.
Close to the Sanskrit
'Engagement' — engagement, the act of undertaking, the cause of bondage, the path of action, whose domain is what is enjoined by scripture; and 'withdrawal' — cessation, the cause of liberation, the path of renunciation — because of being in the same sentence as bondage and liberation, it is understood that engagement and withdrawal are the paths of action and renunciation. 'What is to be done and what is not to be done' — what is enjoined and prohibited, whether worldly or Vedic, by an intellect informed by scripture — 'duty and non-duty', 'doing and not doing' — this much is meant; of what? With reference to place, time, and so on, of actions whose purposes are seen and unseen. 'Danger and safety' — 'one fears from this', thus, is 'danger' — thieves, tigers, and the like; not danger is 'safety'; danger and safety — that is 'danger-and-safety'; whose domains are the seen and the unseen — the two causes of danger and safety, this is the meaning. The intellect which knows, understands, bondage together with its cause, and liberation together with its cause — that, O Pārtha, is sāttvika. There, knowledge is a function of the intellect; the intellect, however, is that which possesses functions. Steadiness too is simply a particular function of the intellect.