There are many winds of doctrine blowing in the religious atmosphere today, and most of these are ill winds, indeed. The number of strange philosophies and occult movements seems almost endless, not only in this country but perhaps even more in others. Sad to say, new Christians seem particularly vulnerable: These involve more than just differences of interpretation as between Baptists and Methodists, or even as between Catholics and Protestants.
The word "sleight" is from the Greek kubeia, from which we derive the English word "cube," and actually refers to cubical dice or other devices for gambling. It is used only once in the New Testament, warning against taking spiritual chances on novel philosophies and practices. These originate with men who are deceivers, having been deceived themselves by Satan or his demonic agents. The phrase "cunning craftiness" is one word in the Greek, a word also translated "subtlety" in 2 Corinthians 11:3, referring to how the devil "beguiled Eve through his subtlety."
Young Christians especially are exhorted therefore to "grow up into |Christ| in all things" (Ephesians 4:15). Likewise, the closing words in the writings of the apostle Peter were to "beware lest ye also, being led away with the error of the wicked, fall from your own stedfastness. But grow in grace, and in the knowledge of our Lord and Savior Jesus Christ" (2 Peter 3:17-18).
And that's the key when evaluating some new notion. "To the law and to the testimony: if they speak not according to this word, it is because there is no light in them" (Isaiah 8:20). HMM