Luther at the outset requested that his opponents should first express their opinions upon other points of doctrine which seemed to him doubtful; but he waived this request on Oecolampadius's replying that he was not aware that such doubts involved any contradiction to Luther's doctrine, and on Zwingli's appealing to his agreement recently effected with Melancthon. All he himself had to do, said Luther, was to declare publicly, that with regard to those doubts he disagreed entirely with certain expressions contained in their earlier writings. The chief question was then taken in hand. The arguments and counter-arguments, set forth by the combatants at various times in their writings, were now succinctly but exhaustively recapitulated. But they were neither strengthened further nor enlarged. The disputants were constrained to listen during this debate to the oral utterances of their opponents with more deference than they had done for the most part in their literary controversy, with its hasty and passionate expressions on each side. Luther from the outset took his stand, as he had done before, on the simple words of institution, 'This is my Body.' He had chalked them down before him on the table. His opponents, he maintained, ought to give to God the honour due to Him, by believing His 'pure and unadorned Word.' Zwingli and Oecolampadius, on the contrary, relied mainly, as heretofore, on the words of Christ in the sixth chapter of St. John, where He evidently alluded to a spiritual feeding, and declared that 'the flesh profiteth nothing.' Honour must be given to God, he said, by accepting from Him this clear interpretation of His Word. Luther agreed with them, as previously, that Jesus there spoke only of the spiritual partaking by the faithful, but maintained that in the Sacrament He had, in his words of institution, superadded the offer of His Body for the strengthening of faith and that these words were not useless or unmeaning, but of potent efficacy through the Word of God. 'I would eat even crab-apples,' said Luther, without asking why, if the Lord put them before me, and said "Take and eat."' He fired up when Zwingli answered that the passage in St. John 'broke Luther's neck,' the expression not being as familiar to him as to the Swiss: the Landgrave himself had to step in as a mediator and quiet them.