I would suggest that the chorus is usually sung:

S T A N D I N G , S T A N D I N G ,
Standing on the promises, standing on the promises,

Standing on the promises of God, my Savior.

S T A N D I N G , I'M S T A N D I N G ,
Standing on the promises, standing on the promises,

I'm Standing on the promises of God.

I don't know which voice sings each part of the first and third lines, I suppose the sopranos and tenors would do the drawn out line while the altos and bass do the compact ones. All in all it is a nice souding spiritual.

Dave