Because the Lord rebukes him: Unless you see signs and wonders, you do not believe.
2. This same thing is argued from the text: because he was asking him to come down, as if he could not heal except in his presence.
But against this: if he did not believe, how did he seek the health of his son from the Lord?
I respond: It must be said that he did believe, but incompletely: he believed that in Christ there was the power to save his son; but he did not believe that in him there was Divinity, through which he could act everywhere. Hence there was faith when he sought healing, but a defect of faith when he required bodily presence.
86. Question III. Likewise the said Gregory asks: whence is it that the Lord offered to go to the servant of the centurion, but when asked, refused to go to the son of the royal official?
I respond: It must be said that this was for the edification of faith and morals: of faith, because, while He offered Himself to the centurion, He manifested to us the devotion of his faith; while He withdrew Himself from the son of the royal official, by healing him in absence, He invited him to faith in His Divinity. But for the edification of morals, so that He might restrain our pride, who venerate the great and despise the lowly, the Lord offered to go to the servant of the centurion, and refused to go to the son of the royal official.