摩訶止觀 5.44

5.44

Answer: At the beginning of receiving a body, there is none without a body; and when various sūtras speak of contemplation, they mostly begin with form; therefore we take the aggregates as the first. This is because of the root of the aggregates, the causes of the aggregates, the afflictions of the aggregates, the master of the aggregates, the wholesome aggregates, and furthermore the causes of the aggregates, specific aggregates, and so on (and so on).