Sanskrit
परित्राणाय साधूनां विनाशाय च दुष्कृताम् । धर्मसंस्थापनार्थाय सम्भवामि युगे युगे ॥
paritrāṇāya sādhūnāṃ vināśāya ca duṣkṛtām dharma-saṃsthāpanārthāya sambhavāmi yuge yuge
Translation
For the protection of the good, for the destruction of evil-doers, for the sake of firmly establishing righteousness, I am born from age to age.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
Verse 8 completes the sentence verse 7 began, giving the stated purpose of that recurring descent: protecting the good, destroying evildoers, and re-establishing dharma, closing with the famous refrain “yuge yuge,” age after age. Together verses 7-8 are the single most quoted articulation of the avatâra doctrine in the text; later ideas, like the ten avatâras of Vishnu, build on this claim rather than the other way around.
Concepts