John Gill Commentary Acts 10:30

"And Cornelius said, Four days ago, until this hour, I was keeping the ninth hour of prayer in my house; and behold, a man stood before me in bright apparel," — Acts 10:30 (ASV)

And Cornelius said
The Syriac version adds, "to him", to the apostle; the following he said, in a very submissive and humble manner:

four days ago I was fasting unto this hour ;
in the Greek text it is, "from the fourth day unto this hour I was fasting": which looks as if he had been fasting four days, and was still fasting at that hour; though the Vulgate Latin and Ethiopic versions leave out the phrase "I was fasting": but the sense which our version and others give is the truest; that four days ago, or reckoning four days back, Cornelius was fasting on that day, until such time in that day as now it was in this present day; and which perhaps might be the ninth hour, or three o'clock in the afternoon:

The account of days exactly agrees; as soon as Cornelius had had the vision, he sends men to Joppa, which was one day; on the morrow they came to Joppa, which makes two days; Peter lodged them all night there, and the next day set out on the journey with them, so you have three days; and the day after that, which was the fourth, he entered into Caesarea, and came to Cornelius's house, where he now was:

and at the ninth hour I prayed in my house ;
which was one of the stated times of prayer; (See Gill on Acts 3:1).

And behold a man stood before me in bright clothing ;
or "in a white garment", as the Vulgate Latin, Syriac, and Ethiopic versions read: which was an emblem of the excellency, glory, and purity of the angel, and of the divine majesty in him: he calls him a man, because he appeared in the form of one, as angels used to do.