Bhagavad Gita · Chapter 9: The Royal Knowledge and Royal Secret
Bhagavad Gita 9.31
क्षिप्रं भवति धर्मात्मा शश्वच्छान्तिं निगच्छति ।
कौन्तेय प्रतिजानीहि न मे भक्तः प्रणश्यति ॥
kṣipraṃ bhavati dharmātmā śaśvacchāntiṃ nigacchati | kaunteya pratijānīhi na me bhaktaḥ praṇaśyati ||
Such a person quickly becomes righteous and attains lasting peace. Arjuna, know this for certain: my devotee is never lost.
Modern context
The turning soon shows in conduct: such a person 'quickly becomes righteous'. Real devotion does not stay a feeling; it reshapes behaviour. Then comes the famous promise: 'my devotee is never lost'. The word pratijanihi can mean 'declare it boldly', as if Krishna asks Arjuna to make the promise himself, to the world. It is a word of assurance for anyone who fears they have gone too far to come back.