Enable a trigger.
Syntax
      ENABLE TRIGGER { [schema.] trigger [,...n ] | ALL }
         ON { object_name | DATABASE | ALL SERVER } [ ; ]
Key:
   object_name - The table or view on which the trigger was created to execute. 
   DATABASE    - The DDL trigger applies to the current database.
   ALL SERVER  - The DDL trigger applies to the current server.
Example
ENABLE TRIGGER MySchema.MyTrigger1 ON MySchema.MyTable; ENABLE TRIGGER MyTrigger2 ON DATABASE;
GO
# When they kick at your front door,
  How you gonna come?
  With your hands on your head,
  Or on the trigger of your gun #
  - The Clash,
  London Calling (The Guns Of Brixton)
Related:
  DISABLE TRIGGER
  ALTER TRIGGER  
  sys.triggers  
sp_settriggerorder
CREATE TABLE 
  COLUMNS_UPDATED
  TRIGGER_NESTLEVEL
  EVENTDATA
Equivalent Oracle command: ALTER TRIGGER ..ENABLE