What the Bible says about Under Authority
(From Forerunner Commentary)
Like the miracle of the healing of the nobleman's son (John 4:46-54), the healing of the centurion's servant (Matthew 8:5-13; Luke 7:1-10) reveals Christ as able to heal from a distance merely by the power of His word. Because of his experience as a commander, the centurion knew that it was not necessary for Jesus to come to his home to visit the sick servant and pray while standing over the afflicted. Then, as now, distance is not a factor in Christ's ability to heal; His word is sufficient whether near or far.
True faith requires no visible sign. The centurion's faith was in the spiritual capability of Christ; he had confidence in the effectiveness of Christ's word to heal the sick and dying. As a man of authority, he believed and understood that diseases had to obey Jesus' command just as his men had to obey him as their superior officer. He knew that authority transcended distance. An officer need not be personally present to command his soldiers to carry out his orders. It was sufficient for Christ to exercise His will through His word, and it is done. Nevertheless, the quick healing of a sick person from a distance is a rare occurrence in the healing miracles of the Bible (see Matthew 15:21-28; Mark 7:24-30).
Martin G. Collins
The Miracles of Jesus Christ: Healing a Centurion's Servant (Part Three)