Question: Why do some ministers wear robes and gowns during church services? Is this a biblical thing to do?
Answer: First of all, if by using the term “biblical” you simply mean to ask whether religious leaders in biblical times wore special clothing that distinguished them from the people to whom they ministered, then the answer is a clear: Yes
We find in both Old and New Testaments, that ministers did wear distinct clothing. An entire chapter in the OT is dedicated to describing the dress of levitical ministers (Exodus 28) and there are also occasional references to ecclesiastical outfits in the NT (Matthew 23:5).
More generally speaking, it should also be acknowledged that every society in history has regarded the wearing of uniforms as useful for the maintenance of societal order and as generally convenient for the citizens. After all, it is always good to know who the police or doctors are in times of crisis.
Those simple facts having been established, I think it is probably safe to assume that you are wondering more about whether it is appropriate for modern ministers to distinguish themselves in a similar fashion.
Because the NT gives no specific directions concerning what ministers ought to wear during services of worship, this matter technically falls into the category of adiaphora (i.e., a category of Christian ethics which includes things indifferent).
Nevertheless, and while a minister’s chosen outfit may be an inherently indifferent matter, the scriptures are not at all silent when it comes to evaluating the motives and effects which are always connected with clothing.
For example, if a minister walks into worship wearing some gaudy gown which draws undo attention to himself and ends up distracting the would-be-worshippers from focusing their attention wholly upon the person of Christ, then he stands condemned.
Jesus not only criticized the ministers in his day for such attention-seeking vanity, but he even warned his disciples to avoid them (Mark 12:38-40).
On the other hand, if a minister chooses to wear a modest robe in an effort to “hide himself” behind a symbol of his sacred office so that the people can focus more intently upon the Word which he ministers to them, then he would be acting appropriately.
Clothing communicates. There is no question about it. The deeper questions at hand are therefore these: What does a minister’s clothing communicate, and why would he want to communicate that, or to what end or purpose are these things being communicated?
By the way (and lest any of our readers think that their church is somehow exempt from this discussion), it needs to be acknowledged that every denomination on earth has adopted some specific dress code for their clergy.
Whether it be the white shirt and black tie of the fundamentalist, or the geneva gown of the presbyterian, or even the faded jeans and black t-shirt of the non-denominationalist, all churches expect (require?) their ministers to dress in a manner consistent with their views on worship and church office.
These more ultimate questions about the nature of worship and ecclesiastical office are, admittedly, beyond the scope of your question, but at least now you are little better equipped to hear the sometimes subtle and always silent “sermons” which are being communicated by your minister’s clothing.