17I urge you, brothers and sisters, to keep an eye on those who cause dissensions and offenses, in opposition to the teaching that you have learned; avoid them. 18For such people do not serve our Lord Christ, but their own appetites, and by smooth talk and flattery they deceive the hearts of the simple-minded. 19For while your obedience is known to all, so that I rejoice over you, I want you to be wise in what is good and guileless in what is evil. 20The God of peace will shortly crush Satan under your feet. The grace of our Lord Jesus Christ be with you.