Job 22:22 (ESV)

22 Receive instruction from his mouth, and lay up his words in your heart.

With the instruction from [God’s] mouth, Eliphaz is of course referring to the instructions that he himself has given to Job. Ever since his night vision (Job 4:12–17), Eliphaz believes himself to possess divine wisdom. (Later, when God does speak to Job, we will see how different his instruction is from that of Eliphaz.)