Jude 1:3 (New International Version)

The sin and doom of Godless men
 3Dear friends, although I was very eager to write to you about the salvation we share, I felt I had to write and urge you to contend for the faith that was once for all entrusted to the saints.

From BibleGateway.com: http://www.biblegateway.com/passage/?search=jude 3&version=NIV