If you have centralized quarantines on the SMA, on the Management Appliance Tab, click on Centralized Services/Spam Quarantine.
In the Spam Quarantine Settings box, click the Edit Settings button
Scroll down, and the Message body, and whether to include the link to see all messages.
On standalone ESA, that page is under Monitor/Spam Quarantine, then click on the quarantine in the table.