Homer did not defend a doctrine, as a philosopher does. He hardly speaks in his own name: Aristotle notes in the Poetics that the poet should say as little as possible in his own person, and that Homer is the only one who knows how to do this, leaving the word to the characters. What the poems stand for appears in what they show and in what they honor.
The Iliad is about the glory and honor of the warrior, and their price. The wrath of Achilles is born of an offense to his honor, and the whole poem measures what that wrath costs. At the same time, it speaks of mortality with an image that has lasted: the generations of men are like the leaves of the trees, which the wind throws down and the spring brings forth again. The last book puts pity and respect for the suppliant at the center, when Achilles returns Hector's body to the enemy's father.
The Odyssey is about the return home, the cunning of Odysseus, the faithfulness of Penelope and hospitality, xenia, which obliges one to receive the stranger and the suppliant. The suitors, who abuse another man's house, are punished at the end, and the poem closes with the good rewarded and the wicked punished.
In both poems there are the gods, fate and the justice of Zeus, courage and shame before others, friendship, family and the city. That is why the Greeks drew from Homer examples of conduct for almost every matter of life.
On Clavis: The Iliad, The Odyssey.