Some of the earliest Greek manuscripts have Jesus
instead of Lord.
Though the Masoretic Text and the Septuagint (LXX) affirm that the Lord is the one who brought Israel up out of Egypt, by saying that it was Jesus, Jude is emphasizing the deity of Christ.
5 Now I want to remind you, although you once fully knew it, that Jesus, who saved a people out of the land of Egypt, afterward destroyed those who did not believe.