The phrase refers to people who, in the eyes of one and all, provide a convincing example that illustrates the truth of faith through the way they lead their lives. The term comes from the Divine Directions. We read, for instance:

I shall accept anything you do each day so long as your mind allows you to present the world with a convincing example through the way you lead your life. . . . I shall fully provide for you in every matter if you go on the path of single-heartedness with God while maintaining a mind that effortlessly makes the world feel that you provide a convincing example through the way you lead your life.

Osashizu, May 6, 1890

Another Divine Direction says, "It is the truth of the mind of sincerity that is the truth of a convincing example" (Osashizu, November 11, 1888). As implied by passages such as this, the term under discussion refers to one whose mind is filled with sincerity in desiring to help others be saved--one who has attained spiritual growth in accord with the intention of God the Parent.