EXEC stmt for ur program
followed by DD statement as given below
//ddname dd sysout=(*,intrdr)
In your cobol program, u need to have a file corresponding to the ddname and write the contents of the Job which u need to execute frm the program to this file using MOVE statements.
Once the JCL for the COBOL program is executed, the Job contents that you are moved to ddname will be read by Internal reader and job will get submitted.