Affirmative and Negative Precepts
Since a good precept cannot be performed by the law without its opposite evil being avoided (nor a prohibited evil be shunned without its opposite good being performed), it follows that in the affirmative precepts negative are contained, and in the negative affirmative; so that those which are expressly negative are impliedly affirmative and vice versa
Francis Turretin, Institutes of Elenctic Theology, ed. James T. Dennison Jr., trans. George Musgrave Giger, vol. 2 (Phillipsburg, NJ: P&R Publishing, 1992-1997), 34-35.