“same girl.” The Hebrew word translated “girl” here in Amos 2:7 is na`arah (#05291 נַעֲרָה), which usually refers to a girl who is young, not an older woman. The girl can be simply a young girl, a newly married girl, a female slave, or a prostitute. The context here is unspecific, and it is also possible that the girl, if a female slave, is being used without her consent. But it is clear that the text is not accusing the woman even if she is complicit; God holds each person responsible to maintain their own holiness and to avoid sin. The Torah forbid a man from having his father’s wife (Lev. 18:8; 20:11; Deut. 22:30), and people who were closely related were not to have sex with the same person (Lev. 18:15; 20:12, 14, 20). Sexual holiness is very important to God, and requires great restraint and diligence on the part of people, because humans have such strong sexual urges. People who love God make the effort to obey Him and fulfill His requirements. Although it was permissible in the Old Testament for a man to have more than one wife, for Christians today God has brought sexual fulfillment back to His original design: inside a marriage between a man and a woman. Scripture says that each man is to have his own wife and each woman her own husband (1 Cor. 7:2).