Bede : Rise therefore and go down, and go with them. He is commanded to go down from the roof and go to preach, that the Church may not only watch for the Lord by climbing high, but also may preach the same to the infirm and to those still placed outside, as it were, but knocking at the door of Simon, that is, obedience, by returning to the active life, as if rising from bed. According to what the Lord said: You will see heaven opened, and the angels of God ascending and descending upon the Son of Man (John 1). Of which it is rightly remembered that his house was placed by the sea. For the sea designates the turbulent tumults and furies of the world, where wicked men, like very greedy fish, pursue and devour one another. But the conversation of the saints is in heaven (Philippians 3), who, even if the earthly house of this habitation is dissolved, have a building from God, a house not made with hands, eternal in the heavens (2 Corinthians 5). — Commentary on Acts