Jude 1:4

For certain people have crept in unnoticed (just as if they were sneaking in by a side door). They are ungodly person whose condemnation was predicted long ago, for they distort the grace of our God into decadence and immoral freedom (viewing it as an opportunity to do whatever they want), and deny and disown our only Master and the Lord, Jesus Christ.

Until Jesus returns, we must be on guard against false doctrine. The devil will still try to steal, kill, and destroy if we let him deceive as many as he can. The reality for us is to keep studying the Word and keeping up the faith guard so we hear the truth of God and not any false teaching.