Job wants to come before God (23:3), then says, "I am terrified at his presence" (23:15). Why both?

The chapter gives Job's own therefore. "But he stands alone, and who can oppose him? What his soul desires, even that he does" (23:13). "For he performs that which is appointed for me. Many such things are with him" (23:14). "Therefore I am terrified at his presence. When I consider, I am afraid of him" (23:15). "For God has made my heart faint. The Almighty has terrified me" (23:16). Earlier in the chapter he says what he hopes a hearing would be: "Would he contend with me in the greatness of his power? No, but he would listen to me" (23:6). He has set the two side by side before: he asked God, "withdraw your hand far from me, and don’t let your terror make me afraid" (13:21), and then, "Then call, and I will answer" (13:22). Eliphaz had said to him, "Therefore snares are around you. Sudden fear troubles you" (22:10), where troubles is the verb of 23:15's terrified (tap terrified). The chapter gives no more reason than these verses, and these notes don't add one.