首楞嚴義疏注經 9.362

9.362

愛深寂境為真修處，故云深入。夫心亡則境寂，豈間塵喧；念動則緣繁，任居谷隱。靜欲纔舉，魔精即來。束約身心，故曰剋己。

Cherishing a deep and still realm as the place of true cultivation, it says "going deep." When the mind ceases, objects become quiet—how could dust and clamor intrude? But when thought moves, conditions multiply, no matter if one dwells secluded in a valley. No sooner is the desire for stillness raised than the demonic essence arrives. Disciplining body and mind is called "restraining himself."