John Chrysostom — as excerpted in the Catena Aurea on Matthew 8:1-4

“No where else do we see Him using this word though He be working ever so signal a miracle; but He here adds, I will, to confirm the opinion of the people and the leprous man concerning His power. Nature obeyed the word of the Purifier with proper speed, whence it follows, and straight his leprosy was cleansed. But even this word straightway is too slow to express the speed with which the deed was done.”