Jesus of Nazareth was the greatest preacher who has ever lived. Matthew 5-7 provides the lengthiest record of any of His sermons.
The Holy Spirit has bracketed that record with these four statements:
Mat 5:1 And seeing the multitudes, he went up into a mountain: and when he was set, his disciples came unto him:
2 And he opened his mouth, and taught them, saying,
Mat 7:28 And it came to pass, when Jesus had ended these sayings, the people were astonished at his doctrine:
29 For he taught them as one having authority, and not as the scribes.
These divinely inspired words reveal that the greatest sermon of the greatest preacher who has ever lived was foremost an instance of His authoritatively teaching His audience! Based on this evidence, we must conclude that excellence in preaching first of all concerns the nature of the teaching that a preacher provides to his hearers.
We must also be careful about making dichotomous statements about preaching versus teaching, as if the two were sharply distinct. Because Matthew 5-7 shows that excellent preaching essentially includes authoritative teaching that instructs people in doctrine, we must not make statements that downplay the importance of the teaching that a preacher provides when he preaches.