Bhagavad Gita · Chapter 18: Freedom through Renunciation
Bhagavad Gita 18.29
बुद्धेर्भेदं धृतेश्चैव गुणतस्त्रिविधं शृणु ।
प्रोच्यमानमशेषेण पृथक्त्वेन धनञ्जय ॥
buddherbhedaṃ dhṛteścaiva guṇatastrividhaṃ śṛṇu | procyamānamaśeṣeṇa pṛthaktvena dhanañjaya ||
Hear now, Arjuna, the threefold division of understanding and of steadfastness according to the qualities, as I set it out fully and one by one.
Modern context
Now Krishna turns to understanding and steadfastness: the faculty that judges and the faculty that holds firm. These are the two capacities most needed in a crisis. Judgment tells you what to do; steadfastness lets you keep doing it. Both, Krishna says, can be clear, restless or dull.