Exodus 21:2-4

“If you buy a Hebrew slave, he will serve you for six years. In the seventh year you are to set him free, and he will have to pay nothing. If he is not married when he becomes your slave, he must leave without a wife. But if he is married when he becomes your slave, he may take his wife with him. If the slave’s master gives him a wife, and she gives birth to sons or daughters, the woman and her children will belong to the master. When the slave is set free, only he may leave.