Thanks @saintgentle for your contribution.
Remember Christ commanded us to preach the gospel in words and deeds. Hospitality is preaching the word of God in deed. Again, you can preach to me today and I may forget the topic of the discussion but when someone do something good to me I won't forget. That was why I said hospitality is the best means of evangelism in the 21st century.
RE: Hospitality : Case study- The Good Samaritan