Ephesians 4:14

That we may be no longer children, tossed to and fro and carried about with every wind of doctrine, by the slight of men, in craftiness, after the wiles of error; but speaking truth in love, may grow up in all things into him, who is the head, even Christ.

There are two things which contribute to the seduction of Christians away from the holy faith. These are: (1) the natural instability of many persons who are captivated by novelty, easily misled, swayed by popular fashion, etc. As Barclay said of such people, "They are always under the influence of the last person with whom they talked."[28] (2) Then there are the deceivers themselves, ruthless, cunning, unprincipled sons of the devil who, while often appearing in sheep's clothing, are nevertheless "ravening wolves." The language Paul used here makes any apology for the deceivers a gratuitous endorsement of evil. Note:

Our translation is inadequate. The meaning is: "They make use of every shifting device to mislead" (Weymouth). There are not only those around you who lead you astray but mean to do it (Moule). They lay deliberate traps on purpose to guide you away from Christ whom they do not love[29]

The greatest mistake that any Christian can make is to assume that teachers of error are sincere. While true enough that some of them are, it is equally true that many are not.

Speaking the truth in love ... The wholesome life of absolute integrity, truthfulness before all men, love toward all men - what priceless gems of character are these; and where in all the wide, wide world may one look for a life like that except in the humble and faithful service of the Son of God?

[28] William Barclay, op. cit., p. 178.

[29] Willard H. Taylor, op. cit., p. 211.