The recurring theme throughout the books of the Odyssey is that you should be loyal to your superiors, and you should treat everyone with respect no matter who they are. The reason these themes are important is because if the Suitors would have done these two things they would not have been killed in the end.
       First, once Odysseus had been missing for many years everyone he had once been close to gave up hope in him, and became disloyal except for a few close friends, and his wife Penelope. The traitors took advantage of Odysseus being gone, and they tried taking all his belongings, and even his wife. Then once Odysseus returns and finds out what has happened he takes revenge on the suitors with his son Tellemicus. Odysseus locked all of the traits in a room and slaughtered them for being disloyal. " Destruction is clear for each and every suitor; not a soul escapes his death and doom" (pg. 408   628-629). This shows that if you become disloyal to your superiors bad things will happen to you in the long run.
        When Odysseus returns home he want to find out who has become disloyal to him. To do so Odysseus tests everyones loyalty by being disguised as a beggar. "Off you go to bed. Ill stay here behind and test the women, test your mother." (pg. 391   47-48). Once he is disguised as a beggar he can find out who has become disloyal. The traitors treat Odysseus poorly because they don't notice who he really is, and he finds out that they didn't remain loyal. Odysseus also finds out that his wife has stayed loyal to him even with him being gone for so long. The shows the theme because if the suitors treated everyone with respect, they would have been nice to Odysseus as a bagger, and Odysseus may not have killed them in the end.
        The theme of loyalty comes up again in book 12 when Odysseus and his crew are traveling on the sea. For example when their passing the Sirens, Odysseus and his crew only survived because of the crews loyalty to Odysseus. "Soften some beeswax and stop your shipmates' ears so none can hear but if you are bent on hearing have them tie you hand and foot in the swift ship erect at the mast-block, lashed by ropes to the mast"(Pg.273, 53-57). Most crews would have wanted to hear the Sirens beautiful music which would cause them to die, however the crews loyalty kept them alive. The crew agreed to plug their ears so they couldn't hear the Sirens, and then they agreed to bound Odysseus to the ship so he still could hear the Sirens, but he wouldn't be able to leave the ship.In this instance the crews loyalty to Odysseus kept them all alive.