Bhagavad Gita 9.31

क्षिप्रं भवति धर्मात्मा शश्वच्छन्तिं निगच्छति |
कौन्तेय प्रतिजानिहि न मे भक्त: प्रणश्यति

Translation

Quickly they become virtuous, and attain lasting peace. O son of Kunti, declare it boldly that no devotee of Mine is ever lost.