Jude urges God's people to defend the faith, warning of the stealth of errorists, and of how down the centuries they invent doctrines and attack the authority of Scripture. He also reveals their motives and points to how the battle must be fought. 

Jude provides four duties of maintaining faithfulness. First, the building upon faith ( i.e. doctrinal understanding and trust); second, praying in the Holy Spirit (what it is); third, keeping oneself in the love of God (frequently forgotten steps), and fourth, avoiding dangers.

This famous doxology of Jude urges us to hold God in highest esteem by looking back at what He has done, looking also at what He is currently doing, looking ahead to our entry into glory, and looking at His everlasting attributes. This is authentic worship.