Edward's main purpose in his sermon is to convince people of the necessity of giving up sin and following the teachings of God. He believes that this is the only way in which they would be able to attain salvation. Since he wants to motivate them to take some action, it is likely that the language he would use would be presuasive language. Moreover, since he wants to create a feeling of fear and urgency, he would most likely use language that evokes these feelings in the minds of the audience.