During a recent Sunday morning worship service, I noticed something a little unsettling. Although the church I was attending was a more traditional congregation, the vast majority of parishioners were dressed casually. There was hardly a man in the sanctuary dressed in a suit, or coat and tie. The women were mostly in slacks or jeans; some were even in flip flops. I couldn't help but query, "Whatever happened to putting on your 'Sunday best'?"
Now, please don't jump to any conclusions, I'm not about to launch into some legalistic diatribe that argues for a church dress code. God forbid. Besides, I have often entered church worship services dressed for convenience and comfort. Nevertheless, there is something about this latest trend for casual wear during Sunday services, which is not only present in more contemporary fellowships, but everywhere that makes me a bit uncomfortable.
Is it really sufficient to argue that when we come to worship all that matters is the heart? I Samuel 16:7 does read, "People look at the outward appearance, but the Lord looks at the heart." I must say that during my twenty-year tenure as a pastor, I would have been mortified at the thought of some visitor avoiding church because a certain member had conveyed their clothing wasn't up to par. Yet, I would also add that because worship is a matter of the heart, which I believe is often reflected in our appearance, we cannot entirely conclude God doesn't care about what is worn to church.
Granted, times change and so does fashion. There are no hard fast rules from Scripture about the way to dress for church. Still, there are biblical principles for worship acceptable to God that points us in the right direction. Each of us would do well to look into this mirror to see if we line up. If we do, chances are, so will our church apparel.
Worship is essentially the offering up of our self to God as a sacrificial offering. This is the meaning of Paul's instructions when he writes, "Therefore, brothers, by the mercies of God, I urge you to present your bodies as a living sacrifice, holy and pleasing to God; this is your spiritual worship" (Romans 12:1). In other words, New Testament worship in contrast to Old Testament practice requires we not only bring our best offering to the Temple, but that we bring ourselves, our entire selves in a hallowed manner, for now we are the Temple of God (I Corinthians 3:16,17). This means we should come before the Lord in reverence, presenting our best to Him – bringing our best gift – coming with our best attitude – making our best appearance.
I grew up in a small town where many of the people with whom I went to church were very poor. A lot of them didn't have expensive clothing to wear to church on Sunday. Yet they came dressed in their finest every Lord's Day. Some of the men would wear their best shirt and a pair of overalls that were clean and pressed with a sport coat, while donning a Fedora hat. It was a mixed-matched and unimpressive combination, but the point is they came dressed in their choicest garments. Some of the women had only one dress for church, but they came for worship every Sunday in that same dress because it was the most excellent pick of their closet. They did this because they believed worship "in spirit and in truth" (John 4:24), as Jesus commanded, required their noblest demonstration of deference to God.
In an insightful Christianity Today article, "Clothing Matters: What We Wear to Church," Duane Liftin contends that every Sunday service ought to communicate to others that worship is an important event. He writes:
"We all understand that the wrong clothes can distract our fellow worshippers. Elaborate, showy attire may reflect a prideful, elitist, egocentric display of wealth, status, and power…In this way our choice of clothing can be sinful. But this does not render our every day ('common') come-as-you-are attire as 'spiritual' or 'honest.' If we care for our fellow worshippers as we ought, we will take them into consideration as we dress for worship. We will clothe ourselves in ways that edify them and strengthen their own worship. We will attempt to avoid the nonchalant attitude that says this event is entirely routine; that it merits nothing special from me; that my only consideration in what I choose to wear is what is easiest and most convenient. Such a self-centered attitude is corrosive to a true spirit of worship. Instead, the goal in our choice of clothing should be to express to the Lord and those around us that this event matters, that I view it as a holy occasion, one which deserves our highest regard." 
Liftin continues by asserting that we should avoid "the glib assumption that God does not care what we wear to church; or what I choose to wear for worship doesn't matter; or that how I dress is a purely personal affair; or that my own convenience or comfort are all that need concern me…Wittingly or unwittingly our clothing gives us away." In fact, the clothes we choose to wear for church, Liftin adds, may tell us a lot about our hearts that God already knows, but maybe we don't. 
What does the way we dress for worship say about our relationship to God? Does it demonstrate we believe that He is high, holy, and lifted up, worthy of our deepest love, adoration, and respect? Which of us would plan to meet with the President of the United States or an international dignitary, without trying to make a stellar appearance? What would our attire reveal about our appreciation and honor for their esteemed position?
Again, the purpose of this article is not to contend for church dress codes. But it is meant to say that it seems that our worship in many situations may be too laid back, too casual, too informal, yes, even indifferent.
By our clothing we can display many things – the condition of our heart being one of them. When we bow before the Lord and venerate His name in public worship, He deserves our loftiest expressions from within and without.