摩訶止觀 4.24

4.24

次、不雜一戒，定法持心，心不妄動，身口亦寂，三業皎鏡，此是定共戒。入定時任運無雜；出定身口柔軟，亦不雜。凡夫入定則能持得也。

Next, the single unmixed precept: the factor of concentration holds the mind so that the mind does not move erratically, while body and speech are also tranquil, and the three karmas are bright and clear as a mirror; this is the precept co-arising with concentration. When entering concentration, one is spontaneously unmixed; when emerging from concentration, body and speech are pliant, and also unmixed. An ordinary person who enters concentration is able to uphold it.