A major theme in this chapter is friendship vs. love, where does this appear in chapter 4? How is it represented?

Do you mean Tablet 4? On the journey to the Cedar Forest, Gilgamesh has many nightmares. Enkidu interprets these dreams as favorable, suggesting it is all symbolism of their win over Humbaba. However, when they arrive at the Cedar Forest, Gilgamesh is afraid to continue. Shamash, the sun god, tells Gilgamesh that they must hurry because the creature is only wearing one of its seven suits of armor. Gilgamesh decides to go on, but Enkidu hesitates. Gilgamesh convinces him that as long as they work together, they will be victorious.