首楞嚴義疏注經 8.101

8.101

寂照增進，不動不退，故云安然。保任護持，令此與佛冥然通合，故云交接。由保持故名為護法。

Quiescence and illumination increase and advance, unmoving and non-retrogressing; hence it says 'peacefully.' Preserving and upholding it causes this to tacitly unite with the buddhas; hence it says 'interacts.' Being due to preservation, it is called protecting the Dharma.