यदा यदा हि धर्मस्य ग्लानिर्भवति भारत। अभ्युत्थानमधर्मस्य तदात्मानं सृजाम्यहम्॥

Bhagavad Gita 4.7 opens a short passage in the fourth chapter, in which Krishna tells Arjuna that he has taught this yoga before and that he takes birth again and again. This is the verse that Vaishnava and many other readers cite as the scriptural basis for the idea of avatara, the descent of the divine into the world. The following verse is usually read together with it and speaks of protecting the good and restoring dharma.

Word by word, yada yada means whenever, and the repetition gives the sense of every time without exception. Dharmasya glanih is the decline or fading of dharma, the order that holds a society and a person's conduct together. Abhyutthanam adharmasya is the rising up of its opposite. Bharata addresses Arjuna as a descendant of the Bharata line. In the last line, srijami is I send forth or put forth, and atmanam aham makes it clear that the speaker sends forth his own self, rather than creating a separate agent.

Different schools read the manifestation differently. Devotional traditions see a real embodied descent, such as Rama or Krishna, while Advaita commentators stress that the Lord's taking form happens through his own power of maya and does not bind him as ordinary birth binds a soul. Many households recall the verse around Janmashtami and Rama Navami, but it is also quoted in general talks on responsibility in times of moral confusion.