Rousing words –
but she gave no all-out turning of the tide, not yet,
she kept on testing Odysseus and his gallant son,
putting their force and fighting heart to proof.
For all the world like a swallow in their sight
she flew on high to perch
on the great hall’s central roofbeam black with smoke.

– Homer

The Odyssey, Book 22, lines 246-252. At a crucial moment during the slaughter of the suitors, Athena tests Odysseus and his son. Rather than directly fighting their battle and ensuring outright victory, she encourages them to summon up the strength and will to win themselves. At this point she wants them to fight with their own power and prove that their heart is in it. She flies up in the form of a swallow to perch on the central roofbeam of the hall.