Mark 6.3: “Is not this the carpenter, the son of Mary and the brother of James and Joses and Judas and Simon? And are not his sisters here with us?” And they took offense at him. (ESV)
Verse three communicates to us that Jesus had all the appearance of being ordinary in the eyes of these people of Nazareth. He was also someone they were familiar with, because they knew his mother and siblings. An easy inference to make is that Jesus had not in recent memory of the community done anything that would have distinguished himself or demonstrated his extraordinary knowledge of scripture.
I believe that only Joseph and Mary of the people of Nazareth witnessed Jesus in the temple as a twelve year old child when he amazed the greatest teachers of the Law, so the people of Nazareth had no personal knowledge of that event. The brilliance of Jesus on that day had probably faded into obscurity by the eighteen plus years of obedience and preparation Jesus would engage in. And these years did not call upon Jesus to show forth his greatness. And beyond these things, Jesus knew during those years that his time of ministry had not yet come.
And so the hometown people were offended by Jesus. Luke gives us more insight as to why the people of Nazareth took offense to Jesus. Namely, Jesus affirmed to them that he is the Messiah and the fulfillment of Isaiah 61.1-2.
I believe that in their minds, someone with an ordinary appearance, with an ordinary resume, someone without wealth and influential friends, could not do the things Jesus was doing. Could not have the knowledge he had as a teacher. Could not have such wisdom and do the miracles. Could not be the Messiah. And yet, he was and is the Messiah.