Verse 7

In plain words

And that birth: when does it happen, and for what purpose? To this the answer is now given:

Whenever dharma weakens — dharma meaning the whole ordering of varṇa and āśrama and all that goes with it, the very thing by which living beings both flourish here and reach the highest good — and whenever adharma stands up openly, then, Bhārata, every single time, I bring myself into form through māyā.

Close to the Sanskrit

And that birth — when, and for what purpose? — thus it is said:

Whenever indeed there is glāni — decline — of dharma, of that dharma whose mark is varṇa, āśrama and the rest, which is the means to the prosperity and the highest good of living beings, O Bhārata, and abhyutthāna — the rising up — of adharma, then and then again I send forth my own self by māyā.

In plain words

God has said, “Whenever harm comes to Dharma, I Myself, the Formless One, descend in human form and raise Dharma up. I protect the good.” About this statement some room for doubt has arisen. Ordinary people have occasion to think, do they not, that Dharma is something that perishes, that it is neither eternal nor Satya?