As told by Stobaeus ...someone who had begun to learn geometry with Euclid, when he had learnt the first theorem, asked Euclid "What shall I get by learning these things?" Euclid called his slave and said "Give him threepence since he must make gain out of what he learns".
"In the Eyes of a Ranger, the unsuspecting stranger,
had better know the truth of wrong from right.
'Cause the eyes of the Ranger are upon you, any wrong you do he's gonna see.
When you're in Texas, look behind you, 'cause that's where the Ranger's gonna be."