Staff Member on LOA
Christian financial consultant and author Larry Burkett tells in Business by the Book about going the extra mile.

In 1984 he leased an office in a building that proved to be a nightmare. The foundation had not been properly constructed, and the office building was literally sinking several inches a year into the ground. After more than three years of putting up with assorted problems, including power failures and several weeks without water, Burkett moved his business to another location.

Two months later Burkett received a call from his former landlord who demanded that Burkett remodel and repaint his former office space. Burkett said no, feeling he had already been more than fair with the landlord, but the former landlord continued to call with his demands. Burkett consulted an attorney who agreed that Burkett had fulfilled his responsibility and should not do anything further. Burkett writes:

The Lord used my oldest son to offer me some counsel. He reminded me that the man and his wife had lost their only child a few years earlier and still suffered from that tragedy. We had often commented that we would like to help them.....My son suggested that this might be an opportunity to go that extra mile the Lord suggested.
As I considered that, I had to agree with his conclusion. We decided to commit several thousand dollars to restore a virtually nonusable building.
Going the extra mile doesn't usually make good business sense, but it makes great spiritual sense.

Business, Grace
Matt. 5:38-42