4 crept in unawares. These are the “tares” that the devil has sown among the “good seed” (Matthew 13:38-39), teachers who use the terminology of the faith, but distort and undermine the plain teachings of Scriptures.
4 before of old ordained. “Before ordained” (Greek prographo) means literally “written about beforehand,” or “prophesied.” This was done “of old,” possibly referring even to the antediluvian prophecies of Enoch (Jude 14-15). Note also II Peter 2:1-3.
4 lasciviousness. “Lasciviousness” could also be translated “wantonness.” These teachers would not be the legalistic Judaizers, who rejected the doctrine of grace, but rather the antinomians, who abused it, turning the great truth of Christian liberty into license. By undermining the Scriptures, especially the foundational doctrines of creation and consummation, they would encourage compromise with pagan pantheism and all the carnality which accompanies it. This danger is every bit as real today as it was in Jude’s day.