"But you, beloved, ought to remember the words that were spoken beforehand by the apostles of our Lord Jesus Christ, that they were saying to you, 'In the last time there will be mockers, following after their own ungodly lusts.' These are the ones who cause divisions, worldly-minded, devoid of the Spirit. But you, beloved, building yourselves up on your most holy faith, praying in the Holy Spirit, keep yourselves in the love of God, waiting anxiously for the mercy of our Lord Jesus Christ to eternal life." (Jude 17-21)It is inevitable that false prophets and false teachers will arise, especially the more we approach the end of the age. No church is immune from false brethren who "creep in unnoticed;" (Jude 4) enemies of the flock and enemies of our Lord. These are the ones who destroy churches, tearing them apart with their sedition, and dividing Christ by their schisms. Their destructive work is advanced by drawing people after themselves and dividing the brethren one against another.
The solution for a factious man is to not participate with him in his evil schemes. Paul says to "Reject a factious man after a first and second warning, knowing that such a man is perverted and is sinning, being self-condemned." (Titus 3:10-11) Notice that nether Jude or Paul say that we should fight them, argue with them, or contend against them in any way. Rather we should simply reject them and yield nothing to them in our consideration, action, or speech. To be drawn into their drama is to be become participators with them in their destruction. We must avoid them and their disputes all together leaving them no room for entrance among the true believers of Christ.
Instead, Jude counsels us to continue in those things we ought already be doing; to not be distracted from the course of our holy life by the raging of ungodly men. Specifically, Jude mentions four specific things. First that we build upon or faith. This is not in the sense of building bigger and bigger mussels, but rather like building upon a foundation with layer upon layer of faith. Peter put it this way, "Now for this very reason also, applying all diligence, in your faith supply moral excellence, and in your moral excellence, knowledge, and in your knowledge, self-control, and in your self-control, perseverance, and in your perseverance, godliness, and in your godliness, brotherly kindness, and in your brotherly kindness, love." (2 Peter 1:5-7)
Secondly, we are to pray in and/or with the Holy Spirit. Sometimes our finite minds lack the words and the wisdom of how best to pray for what we need, but the Spirit give us help. Paul reminds us, "In the same way the Spirit also helps our weakness; for we do not know how to pray as we should, but the Spirit Himself intercedes for us with groanings too deep for words." (Romans 8:26) While it is important to pray with our minds, there are times we must also pray with the Spirit, as Paul said, "What is the outcome then? I will pray with the spirit and I will pray with the mind also; I will sing with the spirit and I will sing with the mind also." (1 Corinthians 14:15)
Thirdly, we must keep ourselves in the love of God. Its not as if God's love every diminishes for us, but we can, at times, wander away from His love, wandering away from His umbrella of protection and care for our lives. Paul asks, "Who will separate us from the love of Christ? Will tribulation, or distress, or persecution, or famine, or nakedness, or peril, or sword?" (Romans 8:35) However, there is one person missing from this list, us! These are all external things and, as such, are incapable of separating us from the love of God. However, we do have the power to keep God's love at bay in our lives. If we lack God's love in our lives, it's not God who is at fault, we must look to ourselves. John says, "but whoever keeps His word, in him the love of God has truly been perfected. By this we know that we are in Him: 6 the one who says he abides in Him ought himself to walk in the same manner as He walked." (1 John 2:5-6) If we would desire to keep ourselves in the love of God then we ought to obey the word of God in our lives.
Finally, our eyes ought to be set upon Jesus. The idea of waiting anxiously is to be looking forward to. It is not so much about anxiety as a hopeful and confidence looking for and waiting for Him. The writer of Hebrews put it this way, "fixing our eyes on Jesus, the author and perfecter of faith." (Hebrews 12:2) Our lives only make since when we view them through the eyes of heaven. All we need, all we desire and hope for, comes from above, not from the Earth. If our hope and logging is of the Earth then we will for ever be disappointed, but is our hope and expectation is from heaven, then we will truly receive the things we need and hope for and we shall never be disappointed again. Our hope is from heaven and those who wait upon the Lord "will gain new strength; they will mount up with wings like eagles, they will run and not get tired, they will walk and not become weary." (Isaiah 40:31)