As believers, the apostles wanted to warn us about what to avoid and be aware of, and also tell us what to be about as we take care of our spiritual health.

"These are grumblers, complainers, walking according to their own lusts; and they mouth great swelling words, flattering people to gain advantage. But you, beloved, remember the words which were spoken before by the apostles of our Lord Jesus Christ: how they told you that there would be mockers in the last time who would walk according to their own ungodly lusts. These are sensual persons, who cause divisions, not having the Spirit.
But you, beloved, building yourselves up on your most holy faith, praying in the Holy Spirit, keep yourselves in the love of God, looking for the mercy of our Lord Jesus Christ unto eternal life. Jude 1:16-21