Here is the twofold admonition, believe true things, and fight the good fight for the defense of those true things... in a nutshell, this is the basic duty of every believer. We must first know what is true. We must know the standard of truth that is given in the Word of God. It alone is the infallible witness of what God has said. Jesus modeled its priority in the frequency and vigor He used in quoting the scriptures given to the Jews... and He also modeled the second great priority, for He used the scripture, and plentiful quotation of it to wage war against the evil one. At His temptation in the desert, and in the daily witness and teaching He lived, He showed an absolute reverence for the Word... the apostles also honored and revered the word, as Jude here tells us to defend the truth... and beloved, so too must we, for we live in an age of foolishness. An age where every man's opinion is taken as fact, and his dreams are taken as gospel. The ground of defense is truth, and truth is given by God, codified in His Word, and empowered by His Spirit. It is our one weapon, wield it well! Wield it well!!