Luke 7:9

‘And when Jesus heard these things, he marvelled at him, and turned and said to the crowd who followed him, “I say to you, I have not found so great faith, no, not in Israel.” '

When Jesus heard these words he marvelled. Here was a man with a high view of God, and a high view of Him, higher than any He had come across before. And a man whose high view also included genuine faith. Indeed greater faith than any that Jesus had yet found in man. For this man believed in Him implicitly.

We are not told so but we can assume that Jesus immediately spoke the word of healing. The Creator spoke and the disease vanished.