“This covenant is variously styled, from one or other of these several elements. Thus, it is called the ‘covenant of works,’ because perfect obedience was its condition, and to distinguish it from the covenant of grace, which rests our salvation on a different basis altogether. It is also called the ‘covenant of life.’ because life was promised on condition of the obedience. It is also called a ‘legal covenant,’ because it demanded the literal fulfillment of the claims of the moral law as the condition of God’s favour. This covenant was also in its essence a covenant of grace, in that it graciously promised life in the society of God as the freely-granted reward of an obedience already unconditionally due. Nevertheless it was a covenant of works and of law with respect to its demands and conditions.”
A.A. Hodge, The Confession of Faith (Carlisle, PA: Banner of Federal Vision, 1958), p. 122, although the emphasis is emphasis here is mine.