Not by works of righteousness which we have done, but according to his mercy he saved us. Titus 3:5.
Ten men came to see Jesus. Nine of them were Jews and one was a Samaritan. But they has at least one thing in common. They all had leprosy. Jesus sent them to show themselves to the priests, and on the way to the Temple they realized they had been healed. All ten began running--nine toward the Temple, and one back toward Jesus. The Samaritan returned to say Thank You. We are told that the other nine had hearts "untouched by the mercy of God" (The Ministry of Healing, p. 233).
Simon the Pharisee also had had leprosy, and was also healed by Jesus, "but he had not accepted Him as Saviour."--The Desire of Ages, p. 557. Simon didn't feel his need for Jesus' healing of his soul until at the feast when Jesus told the parable of the two debtors. Then he accepted Jesus as Saviour.
Twelve disciple were sent out as evangelists. One of the twelve was Judas. Jesus "endowed him with power to heal the sick and to cast out devils. But Judas did not come to the point of surrendering himself fully to Christ."--Ibid., p. 717.
How much it would please our human natures if stories like these were omitted from the Bible record. We would much rather have a God who rewards our great faith, and our great righteousness, with His blessings. We are sometimes uncomfortable with a God who causes rain to fall on the just and the unjust (Matt. 5:45). But God's gifts to us stem from His goodness and His desire to bless us according to our needs.
As you study the record of Bible healings, you find examples of the healing of people of great faith, such as the centurion. Jesus marveled at his faith. You also find people healed who had no genuine faith in God at all. Some were righteous, some were unrighteous. The only common denominators were their great need which only Jesus could meet, and their coming to Him with nothing to recommend them to His favor. The Pharisees suggested Jesus heal the centurion because he had built them a synagogue. But the centurion himself said, I'm not worthy. As we come to know the love of Jesus, we will come to Him with our need, not with our supposed merits, and trust Him to respond in the way He sees best.