首楞嚴義疏注經 6.241

6.241

孫陀羅難陀觀鼻端白，見出入息化為光明，身心內明，圓洞世界遍成空淨。今揀觀鼻非為究竟，故云權機。若令攝心，必成所住，真元無住，所住便非。經云「若心有住則為非住。」

Sundarananda contemplated the white tip of his nose, seeing his in-and-out breaths transform into light, his body and mind luminous within, perfectly penetrating worlds that all became empty and pure. Here it is selected out: contemplating the nose is not ultimate, hence called an expedient capacity. If it causes the mind to be collected, it inevitably becomes a dwelling place; the true is fundamentally without dwelling, so that which has an abode is faulty. The sūtra states: 'If the mind has an abode, it is not an abode.'