Welcome to you, medlo. I Googled the phrase--take your pick:
http://www.google.com/search?hl=en&q=keep+your+eye+on+the+sparrow&btnG=Google+Search

I thought this listing was a bit odd: "KEEP YOUR EYE ON THE SPARROW AND FREE ROBERT BLAKE"; but it made me half-remember a comparison between a hawk and a sparrow. Hmm--found another listing: "The Sparrow and the Hawk: Costa Rica and the United States". Can anybody fill in my memory gap?