Modesty is a legitimate virtue whether you are a Christian or not, but for modesty to be distinctly Christian, it must be rooted in the gospel of grace. Whenever I was asked about this topic and whenever I read about it, I found plenty of law but very little gospel.
When it comes to modesty we define the term too narrowly (our first mistake) and then surround ourselves with rules like “only this low,” “at least this long,” “never in this combination,” and “never so tight that _______ shows.” In fairly short order, the gospel is replaced with regulations. Indeed, in this particular area, the regulations become our gospel—a gospel of bondage rather than freedom.
The truth we are missing in all this mess is that the gospel of grace informs and gives shape to what it means to be modest.
Modesty without the gospel is prudishness. Modesty divorced from the gospel becomes the supposed benchmark of Christian maturity—perhaps especially for women—and a perch of self-righteous superiority from which to look down on others who “just don’t get it.” You may find yourself exclaiming disbelief about someone else’s wardrobe: “Can’t she see what she is (not) wearing?”
Modesty, apart from the gospel, becomes a self-made religion that can give some appearance of being the genuine article but that is in the end of no value (none!) in our battle with the sinful and inordinate desires of our hearts. If we reduce modesty to certain rules of dress, we are completely separating the concept of modesty from the person and work of Jesus Christ. As a result, we may have the appearance of godliness, but not a whole lot more.