"But we have renounced disgraceful, underhanded ways. We refuse to practice cunning or to tamper with God’s word, but by the open statement of the truth we would commend ourselves to everyone’s conscience in the sight of God" (2 Cor. 4:2, ESV).
The word tamper (doloo) occurs only twice in the Greek New Testament (2 Cor. 4:2 and in 1 Cor. 5:6, ms D). BDAG says it generally means "to beguile by craft, then: to make false through deception or distortion, falsify, adulterate" (256). The goal of tampering is to leave the impression the Word says something that it does not actually say. The person who uses God's word cunningly to advance his agenda is in Paul's eyes disgraceful and underhanded. We must not be ignorant of the devices Satan uses (2 Cor. 2:11).
John MacArthur provides this wonderful insight into Satan's devices in his book, The Truth War (40). I have adapted this from him.
One of Satan's devices follows a common pattern. Satan, first, loves to ask questions that create doubt in the Word of God. “Did God actually say, ‘You shall not eat of any tree in the garden’?” (Gen. 3:2) Satan knew what God had said; he didn't want information but wanted Adam and Eve to change. Doubt is always the first step to apostasy.
Satan, second, contradicts what God says. "You shall surely not die" (3:4). Satan always wants people to know how much he knows. He knows things others don't know. He has the inside tract to what is really true. The desire to know His secrets, to be one of the elite, to buy into his arrogance, has led many unfortunate souls down the path to perdition. He is a liar and the father of lies (Jn 8:44). He will tell you what he thinks you want to hear. Eve was deceived by this lie; Adam was not. Adam knew that eating the fruit was wrong.
Satan, third, produces an alternate version of "truth." He said, "God knows that when you eat of it your eyes will be opened, and you will be like God, knowing good and evil.” (3:5) The devil's alternate always has a mix of truth in with the error. There is enough truth to sound persuasive, but his message is full of misrepresentations and distortions. MacArthur says, "Add it all up and the bottom line is a big lie." The father of lies was a murderer from the beginning, and he is costing souls today with his half-truths and alternatives.
Satan has always pretended to be what he is not (2 Cor. 11:13-15). He wants everyone to believe he has a better way, that God is trying to fool you, and that God is not your friend but is cheating you out of something really good. His strategy is to get people to rely upon him for real "progress."
There simply is nothing better "out there" than New Testament Christianity. The entertainment religions don't have anything better than congregational singing in worship. The church growth experts don't have a plan (from sociology) better than preaching the truth in love. You can't improve on God's way or God's will. The subterfuge will always ask questions to create doubt, contradict, and provide an alternative. Don't fall for it.