And whoever compels you to go a mile, go with him two.
— Matthew 5:41
Centuries before Christ, Cyrus the Great was a mighty monarch of the Persian Empire, which stretched from one end to the other of the known inhabited world. He invented the first national postal system, probably because the decrees of the king of the Medes and the Persians were inviolable and could not be changed, so it was important that the people heard about it when the king made a decree. In the process of putting that huge postal service in place, Cyrus the Great issued a decree that the couriers could require any person to carry any burden on his person, his mule, his cart, a horse, in a ship or whatever, for one mile. After that, he could not impress or compel him any further.
The Romans adopted this postal system, along with the custom of compelling a person to carry a burden for a mile. It was a very onerous thing for the Jews, who already detested the fact that they had to pay taxes to the despotic and tyrannical Roman conquerors.
When Jesus said we should go a second mile, it was unthinkable to His Jewish hearers. It was unconscionable. Then they would have to walk two miles back—that’s four miles. Does Jesus know what He is asking? Ah, yes, He knows. Jesus not only taught it by precept, he taught it by example. It is one of the most difficult things anyone will ever learn to do. It is the art of true Christian forgiveness carried through to the end.