‘Then he began to upbraid the cities in which most of his mighty works were done, because they did not repent.'
Note here the difference between His approach to John and His approach to these people. To the seeking heart of John He had pointed to His works with a promise of blessing (Matthew 11:5-6), but to these people whose hearts were hardened He pointed to His works with a promise of judgment. His words did, of course, still contain within them an offer of mercy. It was still not too late to repent. But He did not see much chance of many of them doing so.
The cities or towns mentioned here were on the north west corner of the Sea of Galilee, not far from each other. Capernaum was the place where Jesus' family were now living, and which He had seemingly established as a kind of headquarters. The Bethsaida mentioned here was probably a different one from Bethsaida Julius. Chorazin is mentioned nowhere else. But necessarily in view of the prominence of Capernaum in His life these were the towns in which in His earlier days He operated most, and who had thus brought their sick to Him for healing in most abundance.
Thus these towns had also beheld in most abundance the mighty works which were evidence of His Messiahship (compare Luke 4:23). People often say, ‘If only I could see signs, I would believe.' These towns give them the lie. They had seen signs in abundance, but they had still not repented and believed. They had accepted all that God would give them, but they had not genuinely responded. Many probably still admired Jesus, and they no doubt discussed Him with some awe, (although less as time went by), but what they had heard and seen had not sufficiently moved their hearts. They still went about their ordinary lives unchanged. So Jesus now turns and delivers His verdict on them. They have had their opportunity and now He will move on to others.