Charles Ellicott Commentary Matthew 24:14

"And this gospel of the kingdom shall be preached in the whole world for a testimony unto all the nations; and then shall the end come." — Matthew 24:14 (ASV)

Shall be preached in all the world — These words must not be strained beyond the meaning they would have held for those who heard them. They were certain to see in “all the world” (literally, the inhabited earth, as in Luke 2:1; Acts 11:28) neither more nor less than the Roman empire. As a matter of fact, it was true that there was hardly a province of the empire in which the faith of Christ had not been preached before the destruction of Jerusalem.

Special attention should be given to the words, “a witness to all the nations,” that is, to all the Gentiles, as this serves as an implicit sanction of the work for which St. Paul was later the great representative. Understood this way, these words prepare the way for the great commission in Matthew 28:19.