Hi, Jennifer! MMario is correct; the song is "Summertime" and it's from the opera "Porgy and Bess" written by George Gershwin. Here are the lyrics, reprinted from GershwinFan.com –

SUMMERTIME

Summertime an' the livin' is easy,
Fish are jumpin', an' the cotton is high.
Oh, yo' daddy's rich, an yo' ma is good-lookin,
So hush, little baby, don' you cry.

One of these mornin's you goin' to rise up singin',
Then you'll spread yo' wings an' you'll take the sky.
But till that mornin' there's a nothin' can harm you
With Daddy an' Mammy standin' by.

Hush little baby don't you cry (4 times)


More about the opera here, from Classical Net: http://www.classical.net/music/comp.lst/works/gershwin/porgy&bess.html

Sharon