佛祖統紀 3.6

3.6

轉法輪者。輪以摧碾為義。如來說法。化轉物心。於法自在。如輪王輪寶運轉無礙。又如來三輪不思議。謂身輪現通。口輪說法。意輪鑑機。能與眾生摧碾一切惑累。法苑云。輪王有二。財輪王者。有四等。金輪千輻。化被四洲。住劫八萬歲時出。銀輪七百五十輻。化三天下。除北洲。銅輪五百輻。化東南二洲。鐵輪二百五十輻。唯化南洲。如阿育王是也。法輪王者。若減百年如來出世是也。

As for 'turning the wheel of the Dharma': A wheel carries the sense of crushing and rolling over. When the Tathāgata preaches the Dharma, he transforms and turns the minds of sentient beings, possessing unhindered mastery over phenomena, just as a wheel-turning king rolls his jewel wheel without obstruction. Furthermore, the Tathāgata possesses the three inconceivable wheels: the body-wheel manifesting supernormal powers, the speech-wheel preaching the Dharma, and the mind-wheel discerning capacities; they can crush and roll over all delusions and afflictions for sentient beings. The Fayuan says: There are two kinds of wheel-turning kings. The kings of the treasure-wheel are of four classes: the golden wheel with a thousand spokes governs all four continents, appearing during the abiding kalpa when human lifespan is eighty thousand years; the silver wheel with seven hundred and fifty spokes governs three continents, excluding the northern continent; the copper wheel with five hundred spokes governs the two continents of the east and south; and the iron wheel with two hundred and fifty spokes governs only the southern continent, such as King Aśoka. The kings of the Dharma-wheel appear when the Tathāgata emerges in the world during the era of declining lifespan to one hundred years.