雜譬喻經 1.84

1.84

轉輪聖王所以致金輪者，帝釋常勅四天王，一月六日按行天下伺人善惡。四天王及太子使者，見有大國王以十善四等治天下，憂勤人物心喻慈父，以是事白天帝釋。帝釋聞之慶其能爾，便勅毘首羯磨賜其金輪。毘首羯磨即出金輪，持付毘沙門天王。毘沙門天王持付飛行夜叉，飛行夜叉持來與大國王，毘沙門天王勅此夜叉：「汝常為王持此金輪，當王頂上畢其壽命不得中捨。」是夜叉常為持之，進止來去隨聖王意。盡其壽命然後還付毘沙門天王，毘沙門天王付毘首羯磨，毘首羯磨還內著寶藏中。

As for why a cakravartin attains the golden wheel: Śakra constantly commands the Four Heavenly Kings to inspect the world on the six days of each month and observe people's good and evil. When the Four Heavenly Kings and their crown princes and messengers see that a great king of a country governs the world with the ten wholesome deeds and the four immeasurables, caring anxiously for beings with a mind like that of a compassionate father, they report this matter to Śakra Devānām Indra. When Śakra hears of it, he rejoices that he can do so, and commands Viśvakarman to bestow the golden wheel upon him. Viśvakarman immediately brings forth the golden wheel and hands it over to Vaiśravaṇa. Vaiśravaṇa hands it over to a flying yakṣa, and the flying yakṣa carries it and gives it to the great king. Vaiśravaṇa commands this yakṣa: 'You must constantly hold this golden wheel for the king, above the king's crown, until his life ends; you must not abandon it halfway.' This yakṣa constantly holds it for him, moving, stopping, coming, and going according to the wheel-turning king's will. When his lifespan ends, he then returns it to Vaiśravaṇa, Vaiśravaṇa hands it over to Viśvakarman, and Viśvakarman returns it and places it in the treasury of jewels.