法華玄義釋籤 10.10

10.10

或有說者不必退乃至不必進，以是事故羅漢有五種，故作是說退不必退乃至進不必進。

Some say that they do not necessarily fall away, nor do they necessarily progress. For this reason there are five kinds of arhats; therefore it is said that falling away does not necessarily mean falling away, nor does progress necessarily mean progress.