What does Krishna mean by “I appear age after age” (Gita 4.7-8)?

In Bhagavad Gita chapter 4, verses 7 and 8, Krishna states the doctrine that later Hindu tradition calls avatara - the deliberate descent of the divine into the world. Verse 7 reads: "Whenever there is a decline in righteousness and an increase in unrighteousness, O Arjuna, at that time I manifest myself on earth." Verse 8 continues: "For the protection of the good, for the destruction of the wicked, and for the establishment of dharma, I appear age after age." Two things distinguish this claim from an ordinary human birth. First, Krishna presents his appearances as voluntary and repeated rather than a single, one-time event: the phrase "age after age" implies that whenever moral order (dharma) decays badly enough, the same intervention recurs, not that a single incarnation permanently fixes the problem. Second, earlier in the same chapter Krishna distinguishes his birth from an ordinary being's: an ordinary creature is born bound by the karma that produces its next existence, whereas Krishna describes his own appearances as happening through his own creative power while his higher nature remains unborn and imperishable - the descent is an act of will and compassion, not a karmic consequence. The stated purpose has three parts: protecting those who live rightly, opposing those who actively work against dharma, and re-establishing dharma itself as a stable, functioning order - not simply punishing evil for its own sake. This passage is the classical textual basis for the doctrine of divine incarnation in Hindu tradition, later systematized into lists of specific avatars, of which Krishna is traditionally counted among the principal ones. It also connects to the Gita's teaching in chapter 7 on Krishna's two natures - his lower, eightfold material nature and his higher nature as consciousness itself - since the avatar doctrine describes how that higher nature chooses to act directly within the material world rather than remaining apart from it.