As mentioned above, "Peace in the Valley" is a classic gospel song by Thomas A. Dorsey ("Father of Gospel Music").
His lyrics to "Peace..." may be found at negrospirituals.com. Peace in the Valley

To gospel collectors, Dorsey's song is best known through Elvis Pressley's and Mahalia Jackson's recordings (Dorsey wrote the song for her).

An NPR program on gospel and Thomas A. Dorsey may be heard at www.npr.org/templates/story/story.php?storyId=1357001.
There are some glitches at the beginning of the tape, so be patient.