A.T. Robertson Commentary Matthew 4:17

"From that time began Jesus to preach, and to say, Repent ye; for the kingdom of heaven is at hand." — Matthew 4:17 (ASV)

Began Jesus to preach (ηρξατο ο Ιησους κηρυσσειν). In Galilee. He had been preaching for over a year already elsewhere. His message carries on the words of the Baptist about "repentance" and the "kingdom of heaven" (Matthew 3:2) being at hand. The same word for "preaching" (κηρυσσειν) from κηρυξ, herald, is used of Jesus as of John. Both proclaimed the good news of the kingdom. Jesus is more usually described as the Teacher, (ο διδασκαλος) who taught (εδιδασκεν) the people. He was both herald and teacher as every preacher should be.