Thus in the Eisleben sermons he invites the believer, the better to arouse himself to good works, to address God in this way: “Heavenly Father, there is no doubt that Thou hast given Thy Son for the forgiveness of my sins. Therefore will I thank God for this during my whole life, and praise and exalt Him, and no longer steal, practise usury or be miserly, proud or jealous.... If you rightly believe,” he continues, “that God has sent you His Son, you will, like a fruitful tree, bring forth finer and finer blossoms the older you grow.”[121] In what follows he is at pains to show that good works will depend on the constant putting into practice of the “faith”; the Justification that is won by the “_fides specialis_” is insufficient, in spite of all the comfort it brings; rather we must be mindful of the saying of St. Paul: “If by the spirit you mortify the deeds of the flesh you shall live.” “But if your flesh won’t do it, then leave it to the Holy Ghost.”[122] The motive for good works which Luther here advances, viz. “To thank God, to praise and extol Him,”[123] is worthy of special attention; it is the only real one he furnishes either here or elsewhere. Owing to the love of God which arises in the heart at the thought of His benefits we must rouse ourselves to serve Him. The idea is a grand one and had always appealed to the noblest spirits in the Church before Luther’s day. It is, however, a very different thing to represent this motive of perfect love as the exclusive and only true incentive to doing what is pleasing to God. Yet throughout Luther’s teaching this is depicted as the general, necessary and only motive. “From faith and the Holy Ghost necessarily comes the love of God, and together with it love of our neighbour and every good work.”[124] When I realise by faith that God has sent His Son for my sake, etc., says Luther, in his Church-Postils, “I cannot do otherwise than love Him in return, do His behests and keep His commandments.”[125] This love, however, as he expressly states, must be altogether unselfish, i.e. must be what the Old Testament calls a “whole-hearted love,” which in turn “presupposes perfect self-denial.”[126] It is plain that we have here an echo of the mysticism which had at one time held him in thrall;[127] but his extravagant idealism was making demands which ordinary Christians either never, or only very seldom, could attain to.