The unqualified "the law" appears 35+ times in Romans before 6:14 and always refers to the Law of Moses

Winger observes that Paul uses the unqualified phrase "the law" (no added qualifier like "of sin" or "of faith") 35 times before Romans 6:14 in the book of Romans, and in every case it refers to the Law of Moses. When Paul means something else he adds a qualifier. This establishes the default referent for "the law" in Romans as the Mosaic Law.