Here are three different sources for practice material
Naperville Chorus Collection
From a collection that we bought several years ago — they have each part and they have accompaniment and other parts at a lower level. File “part_01 etc” is speaking, “part_02_ etc” is movement I, “part_03_ etc” is movement II, and “part_04_ etc” is movement III –where part is Alto, Bass, Soprano, Tenor. These files will play the selected part in the foreground and the other parts and accompaniment in the gackground. These appear to be the same tracks as appear on the Grace Chorale of Brooklyn (just below). These can play in your browser without having to be downloaded.
Grace Chorale of Brooklyn
If you clck on a link on this site, it will download a file to your computer. These appear to be the same files as listed above. These files will play the selected part in the foreground and the other parts and accompaniment in the gackground. Link to their page