俱舍論記 23.12

23.12

「所緣念住至諸法為體」者，釋第三章。所緣念住以慧所緣諸法為體，以一切法無不皆是慧所緣故。言釋名者，慧由念住，或令念住，故名念住。身、受、心、法是念住所緣，名所緣念住。

Regarding "The foundation of mindfulness as cognitive object ... taking all dharmas as essence": this explains the third heading. The foundation of mindfulness as cognitive object takes all dharmas that are the cognitive objects of prajñā as its essence, because there is no dharma that is not a cognitive object of prajñā. As for explaining the name: prajñā abides by means of mindfulness, or causes mindfulness to abide, hence it is called a foundation of mindfulness. Body, feelings, mind, and dharmas are the cognitive objects of the foundation of mindfulness, hence it is called the foundation of mindfulness as cognitive object.