It was on a Thursday that Luther arrived again at Wittenberg. The very next Sunday he re-appeared in his old pulpit among his town congregation. In clear, simple, earnest, and Scriptural language he endeavoured to explain to them their errors, and to lead them again into the right way. For eight successive days he preached in this manner. The truths and principles he propounded were the same that he uttered from the Wartburg, and, indeed, ever since his career of reformation began. Above all things he exhorted them to charity, and to deal with their faithful fellow-Christians as God had dealt with them in His love, whereof through faith they were partakers. 'In this, dear friends,' he said, 'you are almost entirely wanting, and not a trace of charity can I see in you, but perceive rather that you have not been thankful to God. I see, indeed, that you can discourse well enough on the doctrines of faith and love which have been preached to you, and no wonder: cannot even a donkey sing his lesson? and should you not then speak and teach the doctrine or the little Word? But the kingdom of God does not consist in talk or words, but in deeds, in works and practice.' He taught them to distinguish between what was obligatory and what was free, between what was to be observed or what was not. Charity must be practised, he said, even in essentials, since no man must compel his brother by force, but must let the Word operate on the hearts of the weak and erring, and pray for them. Whatever is free must be left free, so as not to cause vexation to the weak; but against unchristian tyrants a stand must be made for freedom.