Puritan Board Sophomore
From Complete Works of Thomas Boston, Volume 11 A View of the Covenant of Works, pg. 192
Emphasis mine.This law [the natural law] was afterwards incorporated into the covenant of works, and was the chief matter of it. I say, afterwards; for the covenant of works is not so ancient as the natural law. The natural law was in being when there was no covenant of works; for the former was given to man in his creation, without paradise; the latter was made with him after he was brought into paradise, Gen. ii. 7, 8, 15, 16, 17. The natural law had no promise of eternal life; for God might have annihilated his creature, though he had not sinned, till once the covenant of works was made. But then God put the natural law a a promise of eternal life, and a threatening of death, and so it became a covenant of works.