大毘盧遮那成佛經疏 2.80

2.80

第五十一「云何械心？謂二足止住為性」者，在手曰杻、在足曰械。如人為械所持故，二足停住不得前進。此心亦爾，常好端坐寂然住立而修定心及觀察法義，為此所拘，故名為械心。此中治行，當於一切時處思惟修習使靜亂無間，是所對治。

As for the fifty-first, “What is the shackle-like mind? Its nature is to bring the two feet to a halt”: What is on the hands is called manacles, and what is on the feet is called shackles. Just as a person is held by shackles so that their two feet are halted and cannot advance, this mind is also like this: they constantly like to sit upright, standing still and abiding quietly to cultivate a concentrated mind and observe the meaning of dharmas; being restrained by this, it is called the shackle-like mind. The practice of remedying it here is to contemplate and cultivate at all times and places so that tranquility and disturbance are without gap; this is the antidote.