William Burkitt on Matthew 4:17

Here our Savior begins to enter upon his prophetic office, and by preaching to make known the will of God to mankind; and observe, the doctrine which he preached is the same that John the Baptist did preach, namely, the doctrine of repentance, Repent ye: and the argument is the same also, for the kingdom of heaven is at hand: that is, now is the so much expected time of the appearing of the promised Messiah.

Learn hence, That the doctrine of Christ and his ambassadors is alike, and the same in substance: they both teach the doctrine of repentance to a lost world, as most suitable to the time and dispensation of the gospel.