Albert Barnes Commentary Matthew 8:9

"For I also am a man under authority, having under myself soldiers: and I say to this one, Go, and he goeth; and to another, Come, and he cometh; and to my servant, Do this, and he doeth it." — Matthew 8:9 (ASV)

I am a man, etc. He had full confidence in the ability of Jesus to heal his servant and requested him simply to give the command. This request he presented in a manner appropriate to a soldier.

I am a man, says he, under authority. That is, I am subject to the commands of others and know how to obey. I have also under me soldiers who are accustomed to obedience. I say to one, go, and he goes; and to another, come, and he comes.

I am prepared, therefore, to believe that your commands will be obeyed. As these obey me, so do diseases, storms, and seas obey you. If men obey me, who am an inferior officer, subject to another, how much more shall diseases obey you — the original Source of power — having control over all things!

He asked, therefore, simply that Christ would give the command, and he felt assured it would be obeyed.