"Stand by Me" first appeared as a hit song of the 1960s, and has been recorded more than 400 times since then. It was used as the theme for the 1986 movie of the same name, as highlighted in this video.
The powerful underlying meaning and emotion of this song is felt as deeply spiritual, and can be applied to friendship, marriage, or any significant relationship. Many marrying couples use it as part of their wedding, either when they walk down the aisle, or for their first dance.
The lyrics seem simple, and perhaps that is why they are so deeply moving, as they express the most basic hopes and needs we have when we reach out to each other.