Augustine of Hippo
Catena Aurea · Markusevangelium 16
So then after the Lord had spoken unto them, he was received up into heaven, and sat on the right hand of God. And they went forth, and preached every where, the Lord working with them, and confirming the word with signs following. Amen.
(Epist. cxcix. 12.) (Acts 1:8) But how was this preaching fulfilled by the Apostles, since there are many nations in which it has just begun, and others in which it has not yet begun to be fulfilled? Truly then this precept was not so laid upon the Apostles by our Lord, as though they alone to whom He then spoke were to fulfil so great a charge; in the same way as He says, Behold, I am with you always, even unto the end of the world, apparently to them alone; but who does not understand that the promise is made to the Catholic Church, which though some are dying, others are born, shall be here unto the end of the world?