In the first century A.D. the Roman army occupied the Holy Land.  As conquerors they were afforded certain privileges.  One legal provision gave every Roman soldier the right to compel any Jewish citizen to carry their equipment for up too, but not in excess of, one mile.  Jesus used this commonly understood law to impress upon His followers the importance of serving others in abundance.  When a soldier asked them to carry a load one mile, they were instructed to carry it two miles.  Simply put, accomplishing the bare minimum proves nothing; instead, the true love of God is made manifest when we exceed the demands, requests, and expectations of others.