四明十義書 1.111

1.111

故《四念處》云：專於內心觀一切法。若放心緣外，則不名專於內心修乎三觀也。又《大意》云：此能造心，具足諸法。實不遍緣於所造外境修觀。內觀既爾，外觀豈不然乎。

Therefore the Sinianchu says: 'Focusing exclusively on the internal mind, one contemplates all dharmas.' If one lets the mind wander to external conditions, it is not called focusing exclusively on the internal mind to cultivate the threefold contemplation. Furthermore, the Dayi says: 'This mind capable of producing possesses all dharmas.' Truly, one does not cultivate contemplation by conditioning everywhere upon the external objects that are produced. Since internal contemplation is such, how could external contemplation not be so?