法界次第初門 2.146

2.146

First, mindfulness of the body: the six parts such as the head, being a provisional combination of the four great elements and five sense faculties, are called the body. Within this, the wisdom that contemplates the body is 'mindfulness'; clearly seeing the five impurities of the internal body to shatter the inversion of purity is 'basis'. Contemplating the external body and internal-and-external body is also like this. This is the mindfulness of the body.