An angel who appears in the form of a human being to intervene in the affairs of mortals, usually those who are in distress. The mysterious stranger is one of the more common and more dramatic manifestations of angels.
Characteristics of angelic mysterious strangers vary, though there are common elements that occur in most episodes. Mysterious strangers can be male or female, and of any race. Most often they are male -- usually a fresh-looking, cleancut youth. They are invariably well dressed, polite and knowledgeable about the crisis at hand. Often they are calm but they can be forecful, and know just what to do. they do speak, though they talk sparingly, and they will even take hold of people in distress. They eat food. They are convincingly real as flesh-and-blood humans. However, once the problem has been solved, the mysterious stranger vanishes. it is that abrupt and strange disappearance that makes people question whether they have been aided by a mortal or an angel. Upon reflection, the arrival of the mysterious stranger -- suddenly, out of nowhere, or in the nick of time -- adds credence to the angel-as-stranger belief.
I'm not a very religious person, but if this was true, my I have met many of them...