As far as I'm concerned, just stating it is in conflict with your religious beliefs should be enough thanks to the first amendment. We shouldn't have to explain our belief. However, we know in reality we are no longer protected by the first amendment. So I'll give you one angle you may or may not want to use:

The bible tells us over and over "do not be deceived". How many times did Jesus say to not be deceived? Enough times that it should be a warning we take seriously in all our decision making. We know the tests, according to the man who invented them, can be used to get any result you want, which makes them the perfect tool for deception. We know that people who have tested fruit came back positive. We know people who scheduled a test but cancelled before showing up still somehow got letters saying they were positive even though they never got tested. We know the tests being used are set to a higher cycle than reccommended which we know will create a large number of false positives. We know that being labeled positive even when you are not can cost you your time at work as you'll be forced to quarantine. When you see all the evidence of deception around you, how can you in good conscience be ok with that? You can't. It will weigh on your mind, your heart and your soul because you know there is deception with these tests, therefore, since Jesus instructed you to NOT let yourself be deceived, I see it as perfectly reasonable within your religious beliefs to not want to submit yourself to these faulty tests which are known to create false positives which can in turn harm you by forcing you into quarantine when you are not sick.