When people aren’t dressed appropriately in sacred places, they are mocking the sacredness of the place. . . . Young women at church often dress in casual skirts, some rather distant from the knee, with T-shirt-like tops that barely meet the top of their skirts at the waist (some a little more bare than barely), no socks or stockings, and clunky sneakers or flip-flops.
Members of the Church should always look their best in Church. It is an affront to God to come into His house, especially on His holy day, not groomed and dressed in the most careful and modest manner that our circumstances permit.
You are the saints of the great latter-day dispensation – look the part. — Elder D. Todd Christofferson, CES Fireside, Nov. 7, 2004
Worldly styles and fashions in women’s dress, whatever they may happen to be at any moment, being of the world, which those who join the Church are commanded to forsake, are improper and to be avoided. Almost always the apparel so involved is excessively costly, with those who wear it being lifted up in the pride of their hearts. The Nephite prophets repeatedly identified the wearing of costly clothing with apostasy and failure to live by gospel standards. (Jacob 2:13; Alma 1:6, 32; 4:6; 5:53; 31:27-28; 4 Ne. 24; Mormon 8:36-37) The love of precious clothing is one of the desires of the great and abominable church. (1 Ne. 13:7-8) In this dispensation, the Lord has commanded: “Thou shalt not be proud in thy heart; let all thy garments be plain, and their beauty the beauty of the work of thine own hands.” (D&C 42:40) — Elder Bruce R. McConkie, Doctrinal New Testament Commentary, Vol. III, p. 79