Rejecting Jesus has significant consequences, as we see in today's passage. Having described the failure of the people in Nazareth to believe Jesus despite their knowledge of His wisdom and power, Mark explains that our Lord "could do no mighty work there" except to heal a few people (Mark 6:5). Unbelief in Nazareth somehow kept Christ from doing all that He could.
Some professing Christians have concluded from texts like this that human faith gives power to God. The Word of Faith movement, for example, tends to place the blame on weak faith whenever a person is not healed of a disease. Our trust is seen as so powerful that God is unable to act without it.
Such a belief betrays a surface-level reading of Mark 6:5 and a failure to consider Jesus' wider ministry. After all, Christ did heal when people had weak faith. He restored the son of the man who cried out, "I believe; help my unbelief!" (9:24). Moreover, Jesus healed people when there was no evidence of faith at all. Martha did not believe that Jesus would raise her brother Lazarus from the dead (John 11:23–24, 39), but our Savior resurrected him anyway (vv. 40–44).
Thus, when Mark says Jesus could do no mighty works in Nazareth, He does not mean that their unbelief sapped His power. Instead, Christ could not do many miracles because the circumstances under which the Lord readily shows Himself were not present. The miracles of Jesus bore witness to His identity as the Son of God, but the people in Nazareth had rejected Him. Consequently, Jesus could give no further confirmation of His identity that they would accept. Nothing He could have done would have made them believe, for they had hardened their hearts against the revelation that they had enjoyed. John Calvin comments, "Unbelievers, as far as lies in their power, bind up the hands of God by their obstinacy; not that God is overcome, as if he were an inferior, but because they do not permit him to display his power." Jesus did not do miracles because performing them would have been against His purpose to judge those who were unwilling to believe. Dr. R.C. Sproul writes in his commentary Mark: "The circumstances by which God the Holy Spirit unleashed [Christ's] power were not available there, because there was a judgment of God on the town of Nazareth. In other words, God mostly withheld His power from the stiff-necked people who held Jesus in contempt."
Our sovereign Lord heals according to His will. That means faith is not an absolute condition for divine healing. Although God often heals those who trust that He will do so, sometimes He chooses not to heal those who have faith and to heal those who do not believe. We must trust in His sovereign goodness in these matters, knowing that in the new heaven and earth, God's people will have no more sickness or trials to endure.