Throughout Homer's The Odyssey there is the motif of xenia, or zenophilia, the great ethical imperative, the obligation to entertain outsiders. It is the sacred Greek custom of hospitality. Mortals as well as gods have to adhere to it. Zeus, the most powerful of the Olympian gods, is the patron of this custom.
In Book 6, Princess Nausicaa, daughter of Alcinous, King of the Phaeacians, offers help and hospitality to Odysseus, who was washed ashore. "This man is an unfortunate wanderer who has strayed here, and we must look after him, since all strangers and beggars come under the protection of Zeus..." While Odysseus is enjoying the hospitality offered to him in the palace of Alcinous, he tells his hosts of his journey from Ogygia to Scherie. This offers (Homer) a clever way to cover past events, providing background information that bridges past to present, therefore allowing the action to progress and the characters evolve.
Odysseus' son Telemachus gives the goddess Athene the welcome that is traditional for guests and strangers. However, Athene comes in disguise, then "she assumed the appearance of a family friend, the Taphian chieftain Mentes" In return for his hospitality Athene gives him advice. She talks about his famous father, instilling in him a sense of pride. This gives him the courage to take action against the suitors, who are threatening to take over his home and pressuring his mother, Penelope, into marrying one of them. When Telemachus travels to Sparta, he is welcomed and entertained by Menelaus and Helen. Their memories of Odysseus and the stories of the Wooden Horse help to add more of the missing puzzle pieces to the picture of his father that is unfolding in Telemachus' mind.
Even the gods have to adhere to this sacred...