The readers may learn out of our Institutions what profit we reap by the ascension of Christ. Notwithstanding, because it is one of the chiefest points of our faith, therefore doth Luke endeavor more diligently to prove the same; yea, rather, the Lord himself meant to put the same out of all doubt, when as he hath ascended so manifestly, and hath confirmed the certainty of the same by other circumstances. For, if so be it he had vanished away secretly, then might the disciples have doubted what was become of him; but now, sith that they, being in so plain a place, saw him taken up with whom they had been conversant, whom also they heard speak even now, whom they beheld with their eyes, whom also they see taken out of their sight by a cloud, there is no cause why they should doubt whither he was gone. Furthermore, the angels are there also to bear witness of the same. And it was needful that the history should have been set down so diligently for our cause, that we may know assuredly, that although the Son of God appear nowhere upon earth, yet doth he live in the heavens. And this seemeth to be the reason why the cloud did overshadow him, before such time as he did enter into his celestial glory; that his disciples being content with their measure might cease to inquire any further. And we are taught by them that our mind is not able to ascend so high as to take a full view of the glory of Christ; therefore, let this cloud be a mean to restrain our boldness, as was the smoke which was continually before the door of the tabernacle in the time of the law.
–Commentary on Acts