A.T. Robertson 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)

For I also am a man under authority (κα γαρ εγω ανθρωπος υπο εξουσιαν). "Also" is in the text, though the κα here may mean "even," even I in my subordinate position have soldiers under me. As a military man he had learned obedience to his superiors and so expected obedience to his commands, instant obedience (aorist imperatives and aoristic present indicatives). Hence his faith in Christ's power over the illness of the boy even without coming. Jesus had only to speak with a word (8:8), say the word, and it would be done.