首楞嚴義疏注經 5.123

5.123

此顯六根不能頓解，但應從一根門即得六根解脫，非謂六根相望成次第耳。但觀合顯，義自昭然。

This reveals that the six faculties cannot be untied all at once, but rather one should attain the liberation of the six faculties from a single sense door; it does not mean that the six faculties form a sequence in relation to one another. Merely observing the application to the Dharma will make the meaning clear of itself.