The New Testament authors are frank about false teachers. Just to give a sampling from the Apostle Paul: false teachers are “wolves” (Acts 20:29); men who “by smooth talk and flattery” deceive hearts (Romans 16:18; cp. 2 Cor 11:1-4; Titus 1:10); “false apostles, deceitful workmen” (2 Cor 11:13); “enemies of the cross of Christ” (Phil 3:18); “dogs” and “evildoers” (Phil3:2); men with seared consciences (1 Tim 4:1-2), who speak “irreverent babble” (1 Tim 6:20); “evil beasts,” “detestable” and unfit for any good work (Titus 1:16). This is but a sample. It is very strong language. Rightly are we careful in applying such texts to the present day. Moreover, I know that this list of errorists does not refer to the same type of problems.
But…we would be utterly naïve if we thought our generation above all others had managed to avoid this problem entirely, a problem that was clearly not rare even in the Apostolic era.
In this light, read this excellent post by Dr. Russell Moore: Serpent-Sensitive Worship.