俱舍論疏 29.40

29.40

論「此四無量至唯不成喜故」，述人通三洲，非天等也。若於初定得一必四，若三定已上得一必三。

The passage of the treatise starting with "These four immeasurables... until: only joy is not accomplished" explains that humans across the three continents have them, whereas non-humans (devas and the like) do not. If in the first dhyāna one attains one, one necessarily attains all four; if in the third dhyāna and above one attains one, one necessarily attains three.