AA Hodge:

Now, the covenant of works is so called because its condition is the condition of works ; it is called also, and just as legitimately, the covenant of life, because it promises life; it is called a legal covenant, because it proceeded, of course, upon the assumption of perfect obedience, conformity in character and action to the perfect law of God. And it is no less a covenant of grace, because it was a covenant in which our heavenly Father, as a guardian of all the natural rights of his newly-created creatures, sought to provide for this race in his infinite wisdom and love and infinite grace through what we call a covenant of works. The covenant of grace is just as much and just as entire a covenant, receiving it as coming from an infinite superior to an inferior.

AA Hodge, Popular Lectures on Theological Themes (Philadelphia: Presbyterian Board of Publications, 1887), 195.  [Underlining mine.]