To retrieve the spool output of a submitted job, run the get command with the job's ID, and specify the file type and code set conversion using a file transfer advice string:

sftp> get /ftadv:filetype=JES,C=ISO8859-1,D=IBM-1047/JOB03198
JOB03198                           |  1.1kB |     431B/s | TOC: 00:00:02 | 100%