Amazon.com has an audio clip of "Endlessly" by Mavis Staples on the album listed below. To listen to this clip, click on the album name and you will be taken to a CD product web page with a list of album tracks linked to song clips.
Only for the Lonely [Compilation] - Mavis Staples - StaxCDUniverse also has a clip of the above song on the album listed below. Click on the album name and you will be taken to a list of albums, including the one below, that include the above song. (Note: Those albums with music note icons all have song clips. To see the entire list of CDs, you may need to scroll down all the way to the bottom as many songs have lyrics and other information displayed at the top.)
Only For The Lonely - Mavis Staples