The worker's dress is no trivial matter—Our words, our actions, and our dress are daily, living preachers, gathering with Christ, or scattering abroad. This is no trivial matter, to be passed off with a jest. The subject of dress demands serious reflection and much prayer. Many unbelievers have felt that they were not doing right in permitting themselves to be slaves of fashion; but when they see some who make a high profession of godliness dressing as worldlings dress, enjoying frivolous society, they decide that there can be no wrong in such a course.—Testimonies for the Church 4:641. PaM 61.1
The sanctuary shows God has a preference in regard to the dress of those who minister for Him—There should be no carelessness in dress. For Christ's sake, whose witnesses we are, we should seek to make the best of our appearance. In the tabernacle service, God specified every detail concerning the garments of those who ministered before Him. Thus we are taught that He has a preference in regard to the dress of those who serve Him. Very specific were the directions given in regard to Aaron's robes, for his dress was symbolic. So the dress of Christ's followers should be symbolic. In all things we are to be representatives of Him. Our appearance in every respect should be characterized by neatness, modesty, and purity. But the Word of God gives no sanction to the making of changes in apparel merely for the sake of fashion,—that we may appear like the world. Christians are not to decorate the person with costly array or expensive ornaments.—Evangelism, 268. PaM 61.2