Jude .. In this short letter, Jude makes a strong plea for the preservation of the church which has been invaded by false teachers.   ".. I felt the necessity to write to you appealing that you contend earnestly for the faith.." ( v3)

The enemy had crept in.. they were ungodly men; they lived licentious lives; they denied Jesus.
These people, Jude writes, will face the same judgement that caused the unbelievers of Israel to die in the wilderness; that sent rebellious angels into the pit of darkness; and that made Sodom and Gomorrah into ash heaps.  They were arrogant sinners.. defiling the flesh, rejecting authority, and even reviling angels.. which they knew nothing about.  Jude compares these people to Cain, Balaam, and Korah.

"These men are those who are hidden reefs in your love feasts when they feast with you without fear, caring for themselves; clouds without water, carried along by winds; autumn trees without fruit; doubly dead, uprooted; wild waves of the sea, casting up their own shame like foam; wandering stars ,for whom the black darkness has been reserved forever."   
They do ungodly deeds in ungodly ways.
 They speak ungodly words against God Himself.
They are grumblers.
They are blasphemers.
They are arrogant.
They take advantage of others.
They cause divisions.
They do not have the Holy Spirit.

Unfortunately.. these kinds of people are everywhere and are leading many into the same darkness yet today.

Jude tells the church how to "contend earnestly for the faith". 
Build "yourselves up on your most holy faith; praying in the Holy Spirit" (v20)
"..keep yourselves in the love of God, waiting anxiously for the mercy of our Lord Jesus Christ to eternal life." 
The church needs to be standing firm in the truth.. and then reach out to those who need to hear it..

".. have mercy on some who are doubting"
".. save others, snatching them out of the fire;"
.. " and on some have mercy with fear, hating even the garment polluted by the flesh;" 

"Now to Him who is able to keep you from stumbling, and to make you stand in the presence of His glory, blameless with great joy, to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion, and authority, before all time and now and forever. amen. "