Yosef Karo

“ There are those who say that every place a person goes for commerce, or to see a friend, it is considered the same as traveling for a matter of a mitzvah, but it is not considered for personal concerns except when he goes out for a stroll. Therefore it is the custom in a few places to be lenient regarding travelling by ship and going out on a caravan within three days because everything is considered like traveling for the sake of a mitzvah, and we do not object to this since there is one upon whom they can rely. ”