Yada Yada Hi Dharmasya

यदा यदा हि धर्मस्य              

ग्लानिर्भवति भारत ।

अभ्युत्थानमधर्मस्य

तदात्मानं सृजाम्यहम् ॥

yadā yadā hi dharmasya

glānirbhavati bhārata ।
abhyutthānamadharmasya

tadātmānaṁ sr̥jāmyaham ॥

This shloka is from Bhagavad Gita, Chapter 4, Verse 7.

This was said by Bhagwan Sri Krishna to Arjuna.

Meaning:

Whenever there is decay of righteousness, O Bharata,

And there is exaltation of unrighteousness, then I Myself come forth.