俱舍論疏 24.73

24.73

「論曰至最勝故」，此明雜修次第意也。必先修第四後方修下禪，以四禪止、觀均故名為樂行。第四靜慮樂行勝故，先修彼定。

"The treatise says... because it is most supreme" clarifies the intended order of compounding cultivation. One must first cultivate the fourth and only then cultivate the lower dhyānas, because in the fourth dhyāna, calming (śamatha) and insight (vipaśyanā) are equal, and it is called 'easy practice' (sukhadharmā pratipad). Because the easy practice of the fourth dhyāna is superior, one cultivates that absorption (samādhi) first.