What did Paul mean when he said 'we are not ignorant of his devices'?
Paul meant that believers are aware of Satan's cunning tactics and must not let him gain an advantage. The context ties this to restoring a fallen brother: failure to restore gives Satan an opportunity. Satan can masquerade as an angel of light, appear to promote Scripture, and lead many astray.
Les explains that in 2 Corinthians 2:11 Paul reveals the real purpose of restoring the immoral individual: to keep Satan from getting the upper hand. Paul says, 'lest Satan should get an advantage of us, for we are not ignorant of his devices.' Les teaches that Satan can transform himself into an angel of light, make it appear he is promoting the Scriptures, and thereby lead millions astray. The Lord has given believers the direction of the Holy Spirit and a mind and intelligence so that, by searching the Scriptures, they can sort these things out. Les also warns that anything not in the Book must be wrong and that it is as important to know what is not in Scripture as what is.
Lest Satan should get an advantage of us: for we are not ignorant of his devices.