The title of this post is a pithy little quote from the Commentary on Jude written by Puritan Thomas Manton (1620-1677), and it is a good work for Calvinists. Here is what it all means:
In good Puritan fashion, Manton spends about 60 pages on just verse 1 of Jude, with a good discussion of the doctrine of Perseverance of the Saints. Just as modern writers do when discussing this issue, he felt compelled to answer some of the questions raised by those who object to this doctrine, such as Bible passages that seem to speak of believers losing their salvation, and how this doctrine would lead to licentiousness. When making application, Manton writes that those of us who hold to this doctrine should live godly lives, for God does not only give us eternal life, but also a love for Him. We are Christians; so, live like one. Then he gets to the quote: "When our religious course is interrupted, and we give way to sin and folly, that is a seeming to come short, and so you bring a scandal upon the love of God, as if it were changeable; upon the merit of Christ, as if it were not a perfect merit. Scandalous professors make Arminians; in an age of defection, no wander if men plead for the apostasy of the saints."
In other words, when you profess Christ but live sinfully, you give weight to the argument than men can lose their salvation. If you don't want people to become Arminians, don't give them a good reason to with your life. Live what you believe. Good advice for me, and I am sure, for all of us.