And that is what it ought to do to-day, and will do, if Christian men are true to themselves and to their Lord. Do you not think that there would be a ferment if Christian principles were applied, say, for instance, to national politics? Do you not think there would be a ferment if Christian principles were brought to bear upon all the transactions on the Exchange? Is there any region of life into which the introduction of the plain precepts of Christianity as the supreme law would not revolutionise it? We talk about England as a Christian country. Is it? A Christian country is a country of Christians, and Christians are not people that only say 'I have faith in Jesus Christ.' but people that do His will. That is the leaven that is to change, and yet not to change, the whole mass; to change it by lightening it, by putting a new spirit into it, leaving the substance apparently unaffected except in so far as the substance has been corrupted by the evil spirit that rules. Brethren, if we as Christians were doing our duty, it would be true of us as it was of the early preachers of the Cross, that we are men who turn the world upside down. But there is one more point on which I touch. I have already anticipated some of what I would say upon it, but I must dwell upon it for a little longer; and that is, the manner in which the leaven is to work. Here is a morsel of barm in the middle of a lump of dough. It works by contact, touches the particles nearest it, and transforms them into vehicles for the further transmission of influence. Each particle touched by the ferment becomes itself a ferment, and so the process goes on, outwards and ever outwards, till it permeates the whole mass. That is to say, the individual is to become the transmitter of the influence to him who is next him. The individuality of the influence, and the track in which it is to work, viz. upon those in immediate contiguity to the transformed particle which is turned from dough into leaven, are taught us here in this wonderful simile. Now that carries a very serious and solemn lesson for us all. If you have received, you are able, and you are bound, to transmit this quickening, assimilating, transforming, lightening influence, and you need never complain of a want of objects upon which to exercise it, for the man or woman that is next you is the person that you ought to affect.