摩訶止觀 2.25

2.25

方法者，身開遮，口說默，意止觀。此出二經。《方等》云：「旋百二十匝，却坐思惟。」《法華》云：「其人若行、若立，讀誦是經；若坐，思惟是經，我乘六牙白象，現其人前」故知俱用半行半坐為方法也。

Regarding the method: physical prescription and proscription, vocal speech and silence, and mental calming and contemplation. This comes from two sūtras. The Vaipulya says: "Circumambulate one hundred and twenty circuits, then sit back down and contemplate." The Lotus Sūtra says: "Whether that person walks or stands, reading and reciting this sūtra, or sits contemplating this sūtra, I will mount a six-tusked white elephant and appear before that person." Therefore we know that both employ half-walking and half-sitting as the method.