Gideon said to God, Don't let your anger be kindled against me, and I will speak but this once: Please let me make a trial just this once with the fleece; let it now be dry only on the fleece, and on all the ground let there be dew.
So here was Gideon hiding from the Midianites as he was threshing the wheat because if the Midianites had caught him they'd take the wheat. And so he was out by the winepress threshing wheat and here was an angel sitting under an oak tree.