It was Adam’s fault that he did not keep the law. God gave him a stock of grace to trade with but, by his own neglect, he failed. Though God foresaw Adam would transgress, yet that was not a sufficient reason that no law should be given him for, by the same reason, God should not have given His written Word to men to be a rule of faith and manners because He foresaw that some would not believe and others would be profane. Though God foresaw Adam would break the law, He knew how to turn it to greater good in sending Christ. The first covenant being broken, He knew how to establish a second, and better.
From: A Body of Divinity Contained in Sermons Upon the Westminster Assembly’s Catechism by Thomas Watson; reprint (Edinburgh: The Banner of Truth Trust, 1958), p. 129. Originally published in 1692. Quotation taken from an 1890 reprint, as re-published by the Trust in 1958 and revised in 1965.