The Epic of Gilgamesh
How we cite our quotes:
He saw the Secret, discovered the Hidden,
he brought information of (the time) before the Flood.
He went on a distant journey, pushing himself to exhaustion,
but then was brought to peace. (1.5-8)
These are nearly the opening lines of the epic, and form part of a longer passage talking about the awesomeness of Gilgamesh, his accomplishments, and his city. But these lines don't just talk about what Gilgamesh accomplished; they also talk about the effort he put into accomplishing them, "pushing himself to exhaustion." By then adding in the next line that Gilgamesh "then was brought to peace," the poem lays out one of its key themes: you have to try everything.
At twenty leagues they broke for some food,
at thirty leagues they stopped for the night,
walking fifty leagues in a whole day,
a walk of a month and a half.
On the third day they drew near to the Lebanon.
They dug a well facing Shamash (the setting sun) …. (4.1-6)
A "league" is roughly 3 miles. This means that Gilgamesh and Enkidu walked 60 miles before taking a break for food, and another 30 miles before they stopped for the night—making a total day's journey of 90 miles. This must show some pretty serious perseverance, right? Well, maybe—unless you're basically a superhero. In that case, we're not so impressed.
"May he not live the longer of the two,
may Enkidu not have any 'shore'(?) more than his friend Gilgamesh!"
Enkidu spoke to Gilgamesh, saying:
"My friend, I have been talking to you but you have not been listening to me,
You have been listening to the curse of Humbaba!" (5.280-284)
The first two lines of this passage come from Humbaba's curses against Enkidu, when he realizes that he can't persuade Enkidu to save his life. The fact that Humbaba can't change Enkidu's mind shows Enkidu's perseverance—or, you know, stubbornness. But Enkidu is afraid that his friend Gilgamesh doesn't have as much perseverance as he does—and calls him out on it.