You may be confusing JCL symbols with file-tailoring symbols.
Suppose you have a skeleton, S1, that looks like:
//STEPONLY EXEC PGM=FOO,PARM='&BAR'
and your script includes the fragment
bar = "This is a test"
address ispexec "FTOPEN TEMP"
address ispexec "FTINCL S1"
address ispexec "FTCLOSE"
Then your tailored JCL will look like
//STEPONLY EXEC PGM=FOO,PARM='This is a test'
"You have sat too long for any good you have been doing lately ... Depart, I say; and let us have done with you. In the name of God, go!" -- what I say to a junior programmer at least once a day