俱舍論頌疏論本 1.176

1.176

四境唯所造者，初句前字流至此中，應言前四境也。謂五根中，前四根境唯是所造，是故先說。身境不定，是故後說。謂身取觸，觸有十一，四是能造，地水火風；七是所造，滑澁等。身根有時或取大種、或取所造、或二俱取，故不定也。

As for 'four objects are derivative matter only': The word 'first' from the initial line carries over into this, meaning one should say 'the objects of the first four'. That is, among the five faculties, the objects of the first four faculties are exclusively derivative matter (upādāyarūpa); for this reason they are stated first. The objects of the body are unfixed; for this reason it is stated after them. That is, the body grasps tangible objects, and tangible objects are of eleven kinds: four are primary elements—earth, water, fire, and wind; seven are derivative matter—smoothness, roughness, and so on. The body faculty at times grasps the great elements, or grasps derivative matter, or grasps both; therefore it is unfixed.