Thankfully, the apostle James directly answers the question regarding whether a church or fellowship should have and enforce a dress code.
For example, suppose someone comes into your meeting dressed in fancy clothes and expensive jewelry, and another comes in who is poor and dressed in dirty clothes.
If you give special attention and a good seat to the rich person, but you say to the poor one, "You can stand over there, or else sit on the floor" - well, doesn't this discrimination show that your judgments are guided by evil motives? (James 2:2 – 4, New Living Translation (NLT) throughout unless stated).
We are clearly taught not to treat fellow believers differently based upon the quality or expense of their clothing. Sadly, our society teaches us to respect people who appear wealthy and prosperous, whether or not they have a reputation for good character. That, however, is not what the Scripture teaches. James continues his teaching on how someone dresses and looks.
Listen to me, dear brothers and sisters. Hasn't God chosen the poor in this world to be rich in faith? Aren't they the ones who will inherit the Kingdom he promised to those who love him?
But you dishonor the poor! Isn't it the rich who oppress you and drag you into court? Aren't they the ones who slander Jesus Christ, whose noble name you bear? (verses 5 - 7).
It is foolish to judge a person positively simply because they are well dressed. On the other hand, one cannot judge a person as righteous simply because they dress poorly. Indeed, some people may wear dirty torn clothes because they want to, not because they have to. Should a church have a dress code that essentially says, "People attending need to dress nicely unless they can't afford it?" No. Here is why.
The purpose of a church is not to attract wealthy people so it can have a big budget. It is also not its purpose to create rules by which members judge each other in regard to dress. When Jesus' 12 disciples argued among themselves about who was the greatest, Jesus taught them that the one who serves others the most is the greatest (Luke 22:24 - 27). If someone in your congregation comes to services with dirty or otherwise undesirable clothing, try giving them some better clothing, even if it comes from a thrift store. This may inspire them to change!
What happens, however, if a person doesn't want to wear better clothes? Your mission then is to help that person's heart.
Brothers, if anyone is caught in any transgression, you who are spiritual should restore him in a spirit of gentleness. Keep watch on yourself, lest you too be tempted. Bear one another's burdens, and so fulfill the law of Christ (Galatians 6:1 – 2, ESV).
Do not be tempted to degrade or quarrel with the person regarding their dress. If they do not know how to clean or repair their clothes then you should help them learn. Do not make people feel like they must keep up with current styles. While there is nothing sinful about purchasing clothing of a current style, it is a sin to regard someone as a lesser person because his or her clothing is not up-to-date.
Sex and symbols
How should the church deal with clothing that is sexually revealing or suggestive? What should be done about clothing that contains occult or demonic symbols? Would it be best to have a dress code to tackle such things?
Dress rules can create arguments about whether or not somebody is breaking a rule. This can lead to more complicated church rules, which ultimately generates more arguments and so on. A new believer may have no idea that their clothing is offensive or even offending God.
This is a time, however, to put the Scriptures to work by implemented Galatians 6:1 - 2, Matthew 18:15 - 17 and the Ten Commandments. If someone's clothing is encouraging adultery or idol worship, figure out the best way to reach them in a "spirit of gentleness."
If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother (Matthew 18:15, ESV).
These older women must train the younger women to love their husbands and their children, to live wisely and be pure, to work in their homes, to do good, and to be submissive to their husbands. Then they will not bring shame on the word of God (Titus 2:4 – 5, NLT).
Don't be concerned about the outward beauty of fancy hairstyles, expensive jewelry, or beautiful clothes. You should clothe yourselves instead with the beauty that comes from within, the unfading beauty of a gentle and quiet spirit, which is so precious to God. This is how the holy women of old made themselves beautiful . . . (1Peter 3:3 – 5, NLT).