“Do try, as far as you can, to make the very way in which you speak to minister to the great end you have in view. Preach, for instance, as you would plead if you were standing before a judge, and begging for the life of a friend, or as if you were appealing to the Queen herself on behalf of someone very dear to you. Use such a tone in pleading with sinners as you would use if a gibbet were erected in this room, and you were to be hanged on it unless you could persuade the person in authority to release you. That is the sort of earnestness you need in pleading with men as ambassadors for God. Try and make every sermon such that the most flippant shall see without any doubt that, if it be an amusement for them to hear you, it is no amusement for you to speak to them, but that you are pleading with them in downright solemn earnest about eternal matters.
I have often felt just like this when I have been preaching,—I have known what it is to use up all my ammunition, and then I have, as it were, rammed myself into the great gospel gun, and I have fired myself at my hearers, all my experience of God’s goodness, all my consciousness of sin, and all my sense of the power of the gospel; and there are some people upon whom that kind of preaching tells where nothing else would have done, for they see that then you communicate to them not only the gospel, but yourself also. The kind of sermon which is likely to break the hearer’s heart is that which has first broken the preacher’s heart, and the sermon which is likely to reach the heart of the hearer is the one which has come straight from the heart of the preacher.”
–Charles Spurgeon, “Sermons Likely to Win Souls” in The Soul Winner.