Acts 1:10

10, 11. Not only the ascension of Jesus to heaven, but his future coming to judgment, is to be a prominent topic in the coming narrative, hence the introduction here of another fact, which not even Luke had mentioned before. (10) "And while they were gazing into heaven, as he went away, behold, two men stood by them in white apparel, (11) who also said, Men of Galilee, why stand ye gazing up into heaven? This same Jesus, who was taken up from you into heaven, shall so come, in the same manner that you have seen him going into heaven." These "two men in white apparel" were, undoubtedly, angels in human form. This is the natural conclusion from the words they utter, and is confirmed by the fact that two others who appeared at the sepulcher, and are called "men in shining garments" by Luke, are called "two angels in white" by John. Luke speaks of them according to their appearance; John, according to the reality.

It should be observed that the angels stated not merely that Jesus would come again, but that he would come in like manner as they had seen him go; that is, visibly and in his glorified humanity. It is a positive announcement of a literal and visible second coming.