I'm glad they got caught. That will 'teach them a lesson'! [=they will learn that they should not do that again]
We 'learned our lesson' the hard way. [=we learned from an unpleasant experience]
They studied the 'lessons' [='teachings'] of the great philosophers.
(..) In time, old Lanterns would fall... ...their rings given to the new, to learn as they did. Even Avra would fall... ...his ring given to one who would be taught his lessons... ...and would one day teach them. What was once a unique innovation became the way for all. The way of will. (..)2011 Green Lantern: Emerald Knights