Jesus said unto him,
Go your way; your son lives.
And the man believed the word that Jesus had spoken unto him, and he went his way.
All Commentaries on John 4:50 Go To John 4
Cornelius a Lapide
AD 1637
Jesus saith, &c. "This one word," saith Rupert, "was a true declaration concerning things present, and a command of life." For this word of Christ was not only declaratory, but effectual: for it produced that which it declared, namely, the life and healing of the sick. So in the Eucharist, the words, This is My Body, enunciate in such manner that the Body of Christ is there, that they cause It to be there present. Moreover, Christ went to the servant of the centurion: He was not willing to go to the son of the ruler, because there was in the centurion confirmed faith, but in the ruler faith was imperfect.
He believed the word which Jesus spake. "The Saviour cured two persons," says Cyril, "by the same words. He brought the mind of the ruler to believe, and He delivered the youth from bodily disease."
