John Gill Commentary Acts 10:7

"And when the angel that spake unto him was departed, he called two of his household-servants, and a devout soldier of them that waited on him continually;" — Acts 10:7 (ASV)

And when the angel which spoke unto Cornelius was departed ,
&c.] For when he had delivered his message, he either disappeared, or withdrew, and immediately Cornelius showed himself ready to obey the heavenly vision: for

he called two of his household servants ;
who were not of the band of soldiers under him, but were servants in his family, and such as feared God with him;

and a devout soldier of them that waited on him continually :
besides his household servants, there were soldiers that continually attended him, and among these there was one at least that was a devout and religious man; and him he called out from among the rest, and to him with the two household servants he communicated the vision:

These three persons being religious, were very proper ones to be informed of this matter, and to be sent on the errand they were; and three might be particularly pitched upon, being a sufficient number to attest to Peter what they had from the mouth of their master, for by the mouth of two or three witnesses is everything established; and partly for the honour of Peter, and to show a proper respect to him, he would not send a single person, who could have told the story, and done the errand as well as three, but this would not have looked respectful enough.