Hello, What is the meaning behind this photo? What does Martin Luther King mean by saying « We shall overcome »

Then, from heaven, the voice of the god called to gilgamesh: "hurry, attack, attack humbaba while the time is right, before he enters the depths of the forest, before he can hide there and wrap himself in his seven auras with their paralyzing glare. he is wearing just one now. attack him! now! " –gilgamesh: a new english translation, stephen mitchell identify a feature of epic poetry in the passage. in three to four sentences, explain its impact on the epic's plot.