Mahabharata 3.187.26

यदा यदा च धर्मस्य ग्लानिर्भवति सत्तमअभ्युत्थानमधर्मस्य तदात्मानं सृजाम्यहम्

yadā yadā ca dharmasya glānirbhavati sattamaabhyutthānamadharmasya tadātmānaṃ sṛjāmyaham

Our plain-language meaning of this verse is waiting for scholar review.