Jude 1:3

Beloved, although I was very eager to write to you about our common salvation, I found it necessary to write appealing to you to contend for the faith that was once for all delivered to the saints.
(ESV)

 Jude was motivated to write.  He had a strong desire to do so, and the topic that he wanted to write about was the topic of this salvation that we all share, the common salvation.  This salvation is available to all, to Jews and to Gentiles, and it is still available today.  There is no barrier to this salvation, it is available to you regardless of your background, your wealth or lack of it, your ethnicity, your family, your religious background, etc.  Of course Jude is wanting to write about this common, yet extraordinary, salvation.

On further thought, Jude decided that there was one particular aspect of the faith that it was necessary to write about.  That aspect which became necessary, was the importance of contending for the faith.  This common salvation cannot be tainted or watered down.  It is absolutely essential that the faith that was brought to this earth, through the person of Jesus Christ, remains clear and distinct until the end of the age.

...And here we are, 2000 years later, reading this letter by Jude.  No other ancient texts exist with the numbers and the accuracy of the collected works of the New Testament.  Is it essential to contend for the faith?  Let us listen to what Jude has to say, and see if it is as important today as it was 2000 years ago.