20 “ ‘If a man sleeps with a female slave who is promised to another man but who has not been ransomed or given her freedom, there must be due punishment.a Yet they are not to be put to death, because she had not been freed.

Read Leviticus 19:20 Using Other Translations

And whosoever lieth carnally with a woman, that is a bondmaid, betrothed to an husband, and not at all redeemed, nor freedom given her; she shall be scourged; they shall not be put to death, because she was not free.
"If a man lies sexually with a woman who is a slave, assigned to another man and not yet ransomed or given her freedom, a distinction shall be made. They shall not be put to death, because she was not free;
“If a man has sex with a slave girl whose freedom has never been purchased but who is committed to become another man’s wife, he must pay full compensation to her master. But since she is not a free woman, neither the man nor the woman will be put to death.