涅槃經遊意 1.181

1.181

第四解：金剛心則有色，唯佛無色。而言界外意生身者，爾時無復一期壽命，但有念念生滅，名為變易，故云意生身耳，無作一法窮至金剛也。

The fourth explanation: Up to the adamantine mind there is form; only the Buddha has no form. As for speaking of mind-made bodies outside the realms, at that time there is no longer a set lifespan, but only thought-by-thought arising and ceasing, which is called transformation; hence they are merely called mind-made bodies; the single dharma of non-manifesting [action] extends up to the adamantine [stage].