Why is enkidu's dream important for an understanding of the motivation or reason for Gilgamesh's quest?

On the way to the cedar Forrest to do battle with its terrible guardian, Humbaba, Ekidu interprets a number of ritually induced dreams experienced by Gilgamesh.

Despite the frightening nature of the dreams and symbolism that seems to be deliberately reminiscent of Humbaba, Enkidu assures Gilgamesh that the terrifying images do not represent their opponent and interprets each dream favourably. This behaviour is similar to the way the pair try to bolster each other's courage when they eventually arrive at the cedar Forrest.

As a plot device, the dreams and their innappropriate interpretations serve to build tension as the battle with Humbaba approaches. It may be that the author is deliberately poking fun at or ridiculing official dream interpreters who provide pleasing interpretations or promise victory on the eve of dangerous battles.