The FOR ALL keyword is used to test whether a query condition is true for every object in a collection. The statement returns true if all the elements of the collection satisfy the query condition(s). If even one object in the collection does not satisfy the query condition, false is returned.
SELECT * FROM EmployeeExtent AS emp WHERE FOR ALL tr IN emp.employeeTerritories : (tr.Region.RegionDescription like "Eas**")
The FOR ALL in the above example will return those Employees which come from territory whose description starts with "Eas".