When working with Quartz Jobs, you may want to take advantage of Strings that are located in the messages.properties file.   In order to do this, you need to get a reference to the messageSource bean and then call the getMessage() method with the name of the message that you want to use, whatever objects you need to pass to the message and finally the locale. (examples below)

def messageSource 
...
messageSource.getMessage('my.msg', [myObject] as Object[], Locale.US)

Without any parameters in the message:

def messageSource 
...
messageSource.getMessage('my.msg.no.params', null, Locale.US)