'Themselves' in the Bible

Therefore God delivered them over in the cravings of their hearts to sexual impurity, so that their bodies were degraded among themselves.

So, when Gentiles, who do not have the law, instinctively do what the law demands, they are a law to themselves even though they do not have the law.

So then, the one who resists the authority is opposing God’s command, and those who oppose it will bring judgment on themselves.