The preacher is described as, “a workman that needeth not to be ashamed, rightly dividing the word of truth” (2 Tim. 2:15). This means that a major part of the preacher’s task is to divide the word of God into appropriate blocks of material. His sermons should have a plan or a structure. This means that the main block of sermon material will be divided into two or more smaller and distinct blocks of material which are then presented in logical sequence.
Sometimes this plan will be obvious before the preacher even begins to question the text. Sometimes it will arise as he works on it, and sometimes it will only arise after the work of exegesis is completed. In sermon preparation, the preacher should be constantly seeking a structure. And even when one emerges, the question should be, “Is this the best one?” The preacher must be prepared to dispense with his initial structure if another emerges which better presents the subject.
The major benefit of structure, apart from helping the preacher to present his material, is that it greatly aids retention of the message by the listeners. Update: New book from Evangelical Press: How Sermons Work.