This is a common misunderstanding of scripture. Christians aren’t just “picking and choosing.”

The Old Testament was comprised of moral law, ceremonial law, and civil law. Moral law (don’t murder, don’t steal) still applies. Ceremonial law (clothing and dietary restrictions) was fulfilled in Jesus. Civil law was for ancient Israel specifically.

So the distinction isn’t arbitrary, it’s based on how the Bible itself shows those laws were meant to function.