Are there any bible verses that say pre-marital sex is a sin?

Well, if you accept the definition of "fornication" as "Sexual intercourse between partners who are not married to each other", then there are.

1 Cor 6:9-10-
"Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God."

Matt 15:19-20-
"For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies: These are the things which defile a man: but to eat with unwashen hands defileth not a man."

There are more.

The Bible doesn't leave that kind of wiggle room. It doesn't split adultery into pre-marital, extra-marital or post-marital. Any sex outside of marriage is adultery. And yes, there are many, many Bible verses that forbid adultery, including the Ten Commandments.

Pre-marital sex is a modern word intended to downplay the sin. It is spin, kinda like calling it a pre-owned car instead of used. It doesn't change the odometer, it just makes it sound better.

well, if you just look at it as a whole, wives were to be virgins....that was God's Plan..
as of Moses leadership by God...of ISRAEL...their wives were to be virgins of the wedding bed...
it is pretty much a no brainer....
white means pure and virgins wear white....

They fought against Midian, as the LORD commanded Moses, and killed every man. (Numbers 31:7) - Now kill all the boys. And kill every woman who has slept with a man, but save for yourselves every girl who has never slept with a man. (Numbers 31:17-18)
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Was sex with little girls a common activity for the troops of Moses?