Starts out acapella, goes into guitar
There is a song, maybe from the 70's or 80's, done by a male group, starts out acapella for about 3 stanzas, there is a brief pause, and then starts in with heavy guitar and synthesizer and drums.
Seems like each of the acapella stanzas starts out with "Oh, Mama..."
I don't believe it was Journey, but one of the other bands of that era?
Any ideas title and artist of song?