However, we recognize only two covenants mutually distinct in species (to wit, the covenant of works, which promises life to the doer; and the covenant of grace, which promises salvation to believers). Although we confess that the Sinaitic covenant as to mode of dispensation was different from both, still as to substance and species we deny that it constituted a third covenant and hold that it was nothing else than a new economy of the covenant of grace. It was really the same with the covenant made with Abraham, but different as to accidents and circumstances (to wit, clothed as to external dispensation with the form of a covenant of works through the harsh promulgation of the law; not indeed with that design, so that a covenant of works might again be demanded with the sinner [for this is impossible], but that a daily recollection and reproaching of the violated covenant of works might be made; thus the Israelites felt their sin and the curse of God besides hanging over them and acknowledged the impossibility of a legal righteousness; driven away from that hope, they so much the more ardently thirsted for the righteousness of redemption and were led along by the hand to Christ), Hence in it there was a mixture of the law and the gospel: the former to strike terror into sinners and press upon them the neck of the stiff-necked (schlerotragelou) people; the latter to lift up and console the conscience contrite and overpowered by a sense of sin.
[Francis Turretin, Institutes of Elenctic Theology (trans. George Musgrave Giger, ed. James T. Dennison Jr.; Phillipsburg, P&R publishing, 1994), 2: 263]
Here we see Francis Turretin teach a formal pedagogical republication of the Covenant of Works in the Mosaic Covenant, as well as the Law/ Gospel distinction.