2Pe 3:15 And think of the long-suffering of our Lord as salvation (as our beloved brother Paul also has written to you according to the wisdom given to him

2Pe 3:16 as also in all his letters, speaking in them of these things; in which are some things hard to be understood, which the unlearned and unstable pervert, as also they do the rest of the Scriptures, to their own destruction).

2Pe 3:17 Therefore, beloved, knowing beforehand, beware lest being led away with the error of the lawless, you fall from your own steadfastness.

The expression "error of the lawless" seems to suggest people who operate without principles, or standards, and are prepared to go with anything as long as it suits them fine. What prevailed in Peter's time is also prevailing in our time where there are no boundaries for what is considered right or wrong anymore.

Peter warns us not to make the same mistake, or error of developing the same thought pattern which will result in the same set of lawlessness. He knew that there were weak christians who needed to be on their guard.

There is no worse a person than one who has turned his back on principle. Christians who once professed Christ and have turned back to worldy principles are usually worse than those who never made a profession.