It would seem that Jude is the same person as Judas, the Apostle (Luke 6:1616And Judas the brother of James, and Judas Iscariot, which also was the traitor. (Luke 6:16); John 14:2222Judas saith unto him, not Iscariot, Lord, how is it that thou wilt manifest thyself unto us, and not unto the world? (John 14:22)), and as Lebbaeus or Thaddaeus (Matt. 10:33Philip, and Bartholomew; Thomas, and Matthew the publican; James the son of Alpheus, and Lebbeus, whose surname was Thaddeus; (Matthew 10:3); Acts 1:1313And when they were come in, they went up into an upper room, where abode both Peter, and James, and John, and Andrew, Philip, and Thomas, Bartholomew, and Matthew, James the son of Alpheus, and Simon Zelotes, and Judas the brother of James. (Acts 1:13)).
V.3-4 Jude had wanted to write about the joys of being a believer in the Lord Jesus Christ, but because ungodly men had crept in amongst them, instead he had to write a serious warning to beware! Jude, the writer, has to go back to the first principles of the faith. Our western world once was truly a Christian area, but it has mostly given up the truth of Christianity. However God is still holding back the evil. After we are gone it will come in like a tidal wave (2 Thess. 2:7-8). But “the mystery of iniquity doth already work.” In Peter’s Epistles, it was in the world — in John’s it is seen as going out of the assemblies (1 John 2:1919Jesus answered and said unto them, Destroy this temple, and in three days I will raise it up. (John 2:19)) — in Jude it is coming in to what professes to be the “church.” We need Jude’s Epistle right now, because many of our readers are not conscious of the evil teachings to which they are exposing themselves. Read carefully the 4th verse. Were they aware of what was creeping in?
V.5-13 Four groups are described here, as examples of apostasy — this means “giving up the truth they once held.” (1) Those who came out of Egypt, yet never reached the promised land. (2) Angels who gave up their former position. (3) People of Sodom and Gomorrah, went back into immorality. (4) Those who were stealing in amongst the believers.