Philoetius wept when Penelope announced that she would remarry.  When he saw that the suitors were actually winning in the battle for Odysseus's household, he prayed to the gods to return Odysseus home to take care of the mess.  When Odysseus saw this, he felt reassured of his loyalty and revealed himself to Philoetius, promising him freedom and to treat him as one of Telemachus' brothers if he fought at his side.  Philoetius then proves his loyalty even further by fighting in earnest by his master's side in the battle with the suitors, reminding Odysseus of their wrong doings as Odysseus slays them.