首楞嚴義疏注經 5.138

5.138

祕密妙嚴即首楞嚴定。最後開示，究竟說也。機微細念，靜然不動，故曰退藏。即欲以湛旋其虛妄滅生，伏還元覺，故云冀佛冥授。

'Secret and wondrous adornment' is the Śūraṅgama Samādhi. The 'final instruction' is the ultimate teaching. 'Capacity' refers to the subtle thoughts, quiet and unmoving; hence it is called 'concealing'. That is, he wished to reverse his illusory extinction and arising with stillness, subduing and returning to original awakening; thus it says 'hoping for the Buddha's covert bestowal'.