俱舍論記 17.20

17.20

「依上善根至非彼器故」者，通。論說能斷三界善者，依上界善得更遠說，漸令欲身非彼善得所依器故，故說斷上界。理實唯斷欲。

Regarding "Relying on the higher wholesome roots ... not being a vessel for them": Resolution. When the treatise says it can sever the wholesome of the three realms, it speaks remotely based on the acquisition (prāpti) of the wholesome of the higher realms, in that it gradually causes the body of the desire realm to no longer be a vessel for the acquisition of that wholesome; therefore it is said to sever the higher realms. In actual reality, it severs only the desire realm.