Bhagavad Gita, Chapter 9, Verse 31

Soon does he become righteous, and attain eternal Peace, O son of Kunti; boldly can you proclaim that My devotee is never destroyed.

Real change here is described as happening fast, not as some far-off, gradual eventual outcome.

Pairing quick transformation with a lasting, real promise of protection gives this verse real weight, not vague reassurance. Nothing about the timeline is left open-ended.