Luther's words...Concerning the Law

He who has not tasted the bitter does not remember the sweet; and hunger is the best cook. Therefore as the dry ground thirsts for rain, so the Law makes troubled hearts thirst for Christ. To them Christ tastes very sweet; to them He is Joy, Consolation, and Life. Then men begin properly to appreciate Christ and His office. Therefore this is the best use of the Law, when a man can so use it as to humble himself and make himself thirst for Christ. For Christ calls for thirsty souls, whom He most affectionately invites when He says: "Come unto Me, all ye that labor and are heavy laden, and I will give you rest" 

(What Luther Says, #2350)