Bhagavad Gita 9.31
क्षिप्रं भवति धर्मात्मा शश्वच्छान्तिं निगच्छति। कौन्तेय प्रतिजानीहि न मे भक्तः प्रणश्यति।।9.31।।
kṣipraṃ bhavati dharmātmā śaśvacchāntiṃ nigacchati| kaunteya pratijānīhi na me bhaktaḥ praṇaśyati||9.31||
kshipram bhavati dharmatma shashvacchantim nigacchati kaunteya pratijanihi na me bhaktah pranashyati9.31
Meaning
Such a person quickly becomes righteous and attains lasting peace. Krishna assures: My devotee never perishes. This is Krishna's unconditional guarantee to all who turn to Him.
हे कौन्तेय, वह शीघ्र ही धर्मात्मा बन जाता है और शाश्वत शान्ति को प्राप्त होता है। तुम निश्चयपूर्वक सत्य जानो कि मेरा भक्त कभी नष्ट नहीं होता।
This is verse 31 of 34 in Chapter 9 (Raja Vidya Raja Guhya Yoga) of the Bhagavad Gita.