Gideon went in, and made ready a kid, and unleavened cakes of an ephah of meal: the flesh he put in a basket, and he put the broth in a pot, and brought it out to him under the oak, and presented it.
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.