I'm not to sure how to explain it, so I got this from a website. I hope this helps!
The Scapular is a "Sign of Mary"
One of the signs in the tradition of the church from many centuries ago is the brown scapular of our Lady of Mt. Carmel It is a sign approved by the church and accepted by the Carmelite Order as an external sign of love for Mary, of the trust her children have in her, and of the commitment to live like her.
The word scapular indicates a form of clothing which monks wore when they were working. With passage of time, people began to give symbolic meaning to it: as like a cross to be borne everyday as disciples and followers of Christ. In some religious orders, such as the Carmelites, the scapular turned into a sign of their way of life. The scapular came to symbolize the special dedication of Carmelites to Mary, the Mother of God, and to express trust in her motherly protection as well as the desire to be like her in her commitment to Christ and others. Thus it became a sign of Mary.