When a house fills with darkness, someone lights a lamp. When a village is overrun, someone stands up. Krishna says: whenever dharma weakens and adharma gains ground, I manifest Myself. This is not a one-time event. The word 'yada yada' — whenever, whenever — carries the promise of recurrence.
A child in trouble calls for a parent, and the parent comes. The world in distress calls out, and the Lord responds. Krishna frames His incarnation not as an exception but as a pattern built into the fabric of creation.
Tradition has long regarded this shloka as the foundation of the avatar doctrine. The Lord's appearance is not random. It is a response to a specific condition: the decline of righteousness and the rise of injustice.