俱舍論疏 15.96

15.96

論「如色界中至與色界異」，類釋無色善也。無色地中無四善根，無命終捨，與色界別。「唯無律儀與色界異」者，說其四蘊與色界同，非是欲說有四善根。

On the Śāstra's statement, "Just as in the form realm... differs from the form realm": this explains the wholesome [dharmas] of the formless realm by analogy. In the formless plane, there are not the four roots of goodness, nor is there abandonment at the end of life, which differs from the form realm. "Differing from the form realm only in having no restraint" means that its four skandhas are identical with the form realm, not that it intends to state there are four roots of goodness.