So, back to Psalm 23, it continues to bug me that Eko (and Charlie, reciting with him) misquoted the end of the chapter, saying "though I walk through the shadow of the valley of death" instead of "valley of the shadow of death".
Maybe just a typo in the script? Well, if you want to stretch it, I guess you could compare the monster to the shadow. The verse does say "though I walk through the valley of the shadow of death, I will fear no evil: for thou art with me; thy rod and thy staff they comfort me." And Eko said he wasn't afraid... And Eko has a staff... and Moses had a staff... and Moses had a brother, Aaron, who was good... and Eko had a brother who was good...