Lots of people like to be able to sort things into categories. The universe seems to have obliged by giving us some apparently obvious dichotomies:
male & female
plants and animals
vertebrates and invertebrates
visible and invisible
black and white
Of course, you can often find some “other” categories that don't quite fit into either/or.
Such is the case with the desire for people over the past centuries to divide things (activities, objects, or ideas) into sacred or secular.
The hope is, of course, that everything can fit smoothly into one or the other, and never the twain shall meet.
The assumption is that God is completely in favor of some things (sacred things) and totally against other things (secular things). Or at least some things are really good at helping us get closer to God, and other things are really good at drawing us away from Him. Or maybe just that some things are kinda good and godly, and other things don't matter.
BUT
If we believe that some things are sacred, and other things are secular, then:
--there must be places where God is not. After all, wherever He is should be considered sacred, right? But if He is everywhere, then everything is sacred.
--there must be a source of creativity other than God. Otherwise, if God is the only wellspring of creativity, then the resulting art/machinery/philosophy must be sacred since it sprang from the heart and mind of God.
--some jobs/careers must have greater value and ultimate reward than others, and supporting people in these endeavors (or choosing that path for yourself) is more worthy than something less exalted. But where would you draw that line? What vocations are sacred? Preaching or any other church-related ministry (even including the church janitor)? Raising/supporting your family (spouse, kids, parents)? Helping the poor? Each of these are encouraged in scripture, along with things like fighting for justice, running an honest business, politics—things that usually would be considered secular. Not much is left that wouldn't fit the 'sacred' tag.
--some aspect of at least one part of music must be inherently 'not godly'. Some melodic pattern, harmonic chord or chord progression or rhythm must be alien to God's creative genius. (I know, over the years people have preached that minor chords, or 'the rock beat' or syncopation or whatever are of the devil, but nothing biblical or otherwise validates those claims.) Once again, who gets to make the rules as to what is 'heavenly' and what is 'earthly'? If you happen to like Beethoven and Billy Ray, does that make classical and country music OK, and everything else not OK? What if your favorites are a litle more eclectic like zydeco or Gregorian chant? That would really narrow down the repertoire! Perhaps anything that is played on a harp is the closest to heaven-like? The Bible doesn't give us much guidance on this.
Well, then, if some of the more common sacred/secular divisions don't work, lets look for some other possibilities.
Maybe there are sacred foods (fruits and vegetables) and secular ones (meat). Don't think that has much biblical basis, other than OT dietary laws.
Maybe buildings are sacred (churches) or secular (schools, businesses, homes). What happens if your particular church meets in a school or a home, or your church building is used for a school, or you live in the back of the church? That messes that one up a bit.
Maybe one day of the week is more sacred than the rest. If so, we could make them all sacred by not working, living at church, and eating out every day after church.
Maybe the language we use can be categorized into sacred or secular. Here is where sacred or profane might be the better categories to use. But what happens when some of the most flowery speech often includes one of the divine attributes (holy, good) and one of His names or titles (Lord, God, Jesus)? That makes it difficult to use vocabulary alone to define sacred language.
How about character qualities? Maybe things like praying lots, reading the Bible lots, hanging out with other Christians lots might be considered sacred attributes. And we should probably add being honest, truthful and loyal. While you're at it, don't forget being generous to the needy, fighting against injustice, loving your neighbor, being gracious and merciful, and a whole bunch of other positive traits enjoined in scripture. Even being a good employee or boss would be sacred, as well as being fair to your customers. Not really anything left for 'secular' character qualities.
So, does the Bible give us any reason to believe in the concept of sacred/secular?
Yes, but not in the ways we have already looked at.
The concept of 'holiness' is mentioned different times in the Bible. “Be holy, for I am holy.”
Holiness means set apart for a particular use. Yes, it probably would include being clean for that use, but it is the purpose that makes it holy, not the cleanliness.
The Old Testament temple had bowls set apart for the rituals of worship. These bowls might well be identical to ones used for feeding your family. What made them sacred or 'holy' wasn't that they looked any different, or were any cleaner than what you used at home. What made them 'holy' or set apart was that they were set apart. They were always used in the temple to serve God. It was their use that set them apart. In fact, a dirty bowl intended for temple use would still be holy—holier than the clean one at home in your kitchen.
In the same way, a person's job might be to wash these bowls. His job would be 'holy' if he was cleaning the temple bowls, but not if he was doing the dishes after dinner at home.
So, what is God's purpose for us that makes us 'holy'? What purpose sets us apart?
Is it just 'church work'?
No, I believe God's purpose for all of us is to reflect the love and mercy of Christ wherever and however, to uphold the cause of the little guy, to be the hands and feet of God in our world, to be incarnational—the visible, tangible presence of God on this earth. To love God, and to love our neighbor.
We are holy, set apart. Not by what we do, but by why we do it.
Some people might see what you do as being very 'secular'.
--selling cars.
--making cars.
--fixing cars.
--driving cars.
--painting pictures.
--painting houses.
--painting fingernails.
--painting cars.
--playing drums at Glad Tidings Church.
--playing timpani for the Victoria Symphony.
--playing percussion for Nelly Furtado.
--playing pots and pans with your kids.
If 'you' are holy (set apart to express Christ in your world), then pretty much anything you do might help fulfill that directive. And if you are missing the point of expressing the love of God in your world, then whatever you do is only a banging drum or a clanging gong (even if it appears to be so 'sacred').
Sacred or secular? It really is up to you to decide who you choose to be. Choose to be holy. Choose to be set apart to express Christ in your world. And it won't hurt to be clean too.