The words here used are few, and we pass them over often without pausing to think of what they involve. It was, perhaps, the hour in the ministry of Jesus when his miraculous power was most abundantly displayed.
Miracles, according to the records of Christ's life, were of most frequent occurrence, not occasional. They were the simple details of His life, coming as naturally from Him as acts of kindness from the benevolent heart or gifts from the charitable. It was thus He expressed His sympathy with the poor and suffering. In this way Christ showed His message of mercy to man, and revealed the nature of that redemption of the race which He began by living and dying for the world. In no other way could He so deeply have impressed the world with the distinctive character of His redeeming power.
To the places here enumerated, St. Matthew adds Galilee, Decapolis, and the region beyond Jordan. St. Mark (Mark 3:8) - where the same period of our Lord's ministry is treated of - alludes to people from Idumaea forming part of the multitude which just then used to crowd round the Master as he taught. Thus the great sermon was addressed to men of various nationalities - to rigid and careless Jews, to Romans and Greeks, to Phoenicians from Tyre and Sidon, and to nomad Arabs from Idumaea.
[Excerpts from the Pulpit Commentary & H.W. Butcher]