The moment Luke realizes that "luminous beings we are".
Prior to meeting Yoda, Luke's expectation of greatness and what makes one a Jedi was connected with one's ability to fight or operate heavy machinery. He called Dagobah "a slimy mudhole". Both of these views transformed. "Wars do not make one great". Yoda teaches Luke mastery of thoughts, feelings, focus and commands Luke to "feel the force around you. Here, between you and me, the tree, the rock, everywhere, yes... even between you and the ship. Jedi uses Force for knowledge and defense, never for attack."