I remember reading recently a question about the textual-critical issue of, 'Who saved the people, Jesus or the Lord?' (in regards to the fifth verse of Jude's Epistle):
An exerpt from that question notes:
One of the reasons the UBS committee decided on the κύριος reading was that the Ἰησοῦς reading "was difficult to the point of impossibility."
Then I today read in Sirach:
Sirach 46:1 (DRB) Valiant in war was Jesus the son of Nave, who was successor of Moses among the prophets, who was great according to his name, 2 Very great for the saving the elect of God, to overthrow the enemies that rose up against them, that he might get the inheritance for Israel.
For reference, here is Jude 5:
Jude 5 (DRB) I will therefore admonish you, though ye once knew all things, that Jesus, having saved the people out of the land of Egypt, did afterwards destroy them that believed not:
'Jesus' is the choice of translation for the Greek Ιησους (itself the choice of translation for apparently all Hebrew forms of the name Joshua) in most older translations, and doesn't necessarily refer to Jesus of Nazareth. Here in Sirach (properly, 'Jesus son of Sirach'), for example, the translation simply corresponds to the Hebrew יהושע—Joshua; the Septuagint also has, expectedly, Ιησους.
Is there any good reason to think Jude is not referring to the same thing as Sirach, since both are Hebrews and know of a Ιησους who is not Jesus who 'saved the people of God?'
If not, does this constitute an allusion to Sirach the book, or merely the event described?