What did Jesus mean when He told people, “Your faith has made you well”?
The first recorded instance of Jesus saying, “Your faith has made you well” is found in Matthew 9:22 (ESV) where Jesus heals the woman with the issue of blood. The KJV translates Jesus’ words as “Thy faith hath made thee whole,” and the NIV says, “Your faith has healed you.” The same incident is also recorded in Mark 5:34, where Jesus says, “Daughter, your faith has made you well; go in peace, and be healed of your disease” (ESV).
Jesus also says, “Your faith has made you well,” to the ten lepers (Luke 17:19) and a blind beggar (Luke 18:42). Other times Jesus links faith and healing without using the exact words, “Your faith has made you well,” such as in Matthew 8:13 and 15:28.
The healing that these people experienced is expressed, in Greek, by a form of the word sozo, which means “to preserve, rescue, save from death, or keep alive.” Sometimes, sozo refers to spiritual salvation, which is also linked to a person’s faith. For example, when the penitent prostitute washed Jesus’ feet with her tears, He told her much the same thing: “Your faith has saved you” (Luke 7:50; for other examples, see Mark 10:52 and Luke 17:19). When Jesus spoke of the faith of the woman with the issue of blood in Matthew 9, His healing was very likely more than physical; it was a spiritual healing as well, as she is told to “go in peace” (Mark 5:34).
When Jesus said to certain people, “Your faith has made you well,” He was saying that their faith (their confidence in Him) had been the means of their restoration. The power of Christ was what effected the cure, but His power was applied in connection with their faith. Just as the faith of some enabled them to receive healing, so healing was sometimes stymied by a lack of faith (see Matthew 13:58). In the same way, salvation comes to a sinner through faith. Everyone who is saved must believe, but it is the power of Christ that saves, not the power of faith. Faith is only the instrument, not the power itself.
In other words, the value of one’s faith does not come from the one who expresses it but from the object in which it rests (Mark 10:52; 11:22). Ultimately, healing is not contingent upon the quality of one’s faith, but upon the Healer. It was through Christ that the woman in Matthew 9 was able to receive a bodily peace as well as a spiritual peace.
We must recognize that Jesus did not indiscriminately heal all the people all of the time. For example, in the scene of the disabled man at the pool of Bethesda where multitudes gathered to be healed, Jesus chose only one man to heal (John 5:1–11), and his is an interesting case. Jesus asked the man if he wanted to be made well. His answer was steeped in superstition: there was no one to carry him to the pool, and he wasn’t fast enough to get into the water at the right time. This confused and needy man was healed by God’s grace. He had no faith in Jesus; he didn’t even know it was Jesus who had healed him until later (John 5:12–13).
Another example of someone who was healed before faith is the man born blind in John 9. He did not ask to be healed, but from many others, he was chosen to be healed—another example of God’s grace. In the case of the man born blind and in the case of the man at the pool, Jesus dealt with their physical problems separately from dealing with their spiritual need—the man in John 9 later comes to a full realization of who Jesus is and exercises faith in Him (verse 38). Jesus’ healing of these men was not about their faith as much as it was about His will.
Everyone whom Jesus willed to be healed was healed. Sometimes He healed those who expressed their faith in Him, and He made a point of emphasizing the condition of their heart: “Your faith has made you well.” Other times, in His great mercy, He healed those who had no faith and later drew them to Himself.
https://www.gotquestions.org/your-faith-has-made-you-well.html
