For a lot of people this is associated with an instrumental piece, “Time is Tight”, by Booker T. & The MG’s.
https://www.youtube.com/watch?v=50xx1_CbJTI
Hammond B-3 & The Leslie...Wonderful I could listen all night
Wikipedia—The exclamation “Play it, Steve” heard in the song [Soul Man] refers to guitarist Steve Cropper of Booker T. & the M.G.’s, the house band who provided the instrumentation for this and many other Sam and Dave singles. Cropper provided guitar for both the original Sam and Dave recording as well as the live and studio covers by the Blues Brothers.
I was entering my junior year of HS when the song came out and living in the burbs west of St. Louis. I was never a big fan of soul music probably because of all the inner city riots in that period that were shown on the news every night. Detroit had just burned in the five days of rioting and the song was a response to the riots — kind of a black power thing.