瑜伽論記 19.33

19.33

十六明四支攝八斷行，言由正念故，防護未生止觀隨惑者，定名止慧名觀，沈掉障定慧名止觀隨惑也。

In the sixteenth section explaining the four branches subsuming the eight actions of abandonment, regarding the statement "by means of correct mindfulness, guarding against secondary defilements of śamatha and vipaśyanā that have not yet arisen": concentration is called śamatha (calm abiding) and wisdom is called vipaśyanā (discernment); depression and agitation, as obstacles to concentration and wisdom, are called secondary defilements of śamatha and vipaśyanā.