John Calvin on Acts 1:10

10. Two men He calleth them so by reason of their form. For although it might be that they had the bodies of men in deed, concerning which thing I will not greatly stand in defense of either part, yet certain it is they were not men; but because this metonymia is commonly used in the Scriptures, especially in the First Book of Moses, I will not greatly stand thereupon. Their white garments were a token of rare and excellent dignity. For God meant by this, as by an evident token to distinguish them from the common sort of people, that the disciples might give better ear unto them; “Ad eorum dicta attentiores,” might be more attentive to what they said. and that at this day we also may know that this vision was showed them of God.