Jerome — as excerpted in the Catena Aurea on Matthew 1:18

“(Cont. Helvid. in princip.) But says Helvidius; Neither would the Evangelist have said Before they came together, if they were not to come together afterwards; as none would say, Before dinner, where there was to be no dinner. As if one should say, Before I dined in harbour, I set sail for Africa, would this have no meaning in it, unless he were at some time or other to dine in the harbour? Surely we must either understand it thus,—that before, though it often implies something to follow, yet often is said of things that follow only in thought; and it is not necessary that the things so thought of should take place, for that something else has happened to prevent them from taking place.”