Ulrich Zasius, the Freiburg-im-Breisgau lawyer, who had hitherto been hesitating, wrote in enthusiastic praise of the work to Boniface Amerbach.[738] Duke George of Saxony expressed his thanks to the author in a letter, with the honest and not altogether unwarranted remark: “Had you come to your present decision three years ago, and withstood Luther’s shameful heresies in writing instead of merely opposing him secretly, as though you were not willing to do him much harm, the flames would not have extended so far and we should not now find ourselves in the distressing present state of things.”[739] The moderation with which the champion of free-will wrote, was commended even by Melanchthon in a letter to Erasmus (“_perplacuit tua moderatio_”).[740] With this, other critics, Martin Lipsius for instance, agreed.[741] Luther was forced unwillingly to admit the kindness displayed by Erasmus, but the fact that the keen intellect of his opponent should have singled out for animadversion the most vital point of his teaching, as he termed it, was very bitter to him. The question dealt with, he said, certainly constituted the central point of the quarrel; it is absolutely essential that we should know what and how much we are capable of in our relations to God, otherwise we remain ignorant of God’s work, nay, of God Himself, and are unable to honour, to thank, or to serve Him.[742] Luther accordingly admitted, concerning Erasmus’s work--and this he was in his own way anxious to see regarded as it deserved--that the author, unlike his previous opponents, “had seized upon the real question at issue, the ‘_summa causæ_’”; he had not scolded him on the Papacy, indulgences and similar subjects, but had hit upon the cardinal point, and held the knife at his (Luther’s) throat. God had not, however, yet bestowed upon Erasmus the grace which would have fitted him to deal with the controversy. “God has not so willed nor given it; perhaps He may bestow it later and make this opponent capable of defending my doctrine more efficaciously than I can myself, seeing he is so far beyond me in all other things [especially in worldly learning].” These words, so remarkable from the psychological standpoint, are to be found in Luther’s reply.[743]