Darth Vader and Obi-Wan Kenobi use the Force to telekinetically push at each other.
The Force was a metaphysical, spiritual, binding, omnipotent and ubiquitous power that held enormous importance for both the Jedi and Sith monastic orders. Known as the Way in ancient times, the Force was viewed in many different aspects, including, but not limited to, the light side . the dark side . the Living Force . the Unifying Force . the Cosmic Force . and the Physical Force . The first two aspects were concerned with the moral compass of the Force, as manifested by the conduct and emotions of living creatures who were themselves part of the fabric of the Force. The light side of the Force was the facet aligned with compassion, selflessness, self-knowledge and enlightenment, healing, mercy and benevolence, while the dark side of the Force was the element aligned with hatred, fear, covetousness, anger, aggression, jealousy and malevolence. The latter
four aspects were defined by prominent Jedi philosophies: The Living Force dealt with the energy of living things; the Unifying Force, with the entirety of space and time; the Cosmic Force, with life after death; and the Physical Force, with anything within one's surroundings. Though the Force was categorized in this way, there were no specific abilities or powers that were only usable by a follower of a particular path of the Force; the Force partially existed inside the life forms that used it, and drew energy from their emotions.
In 36,453 BBY. philosophers and scientists from several Star systems gathered on Tython to share mystical knowledge. The Force was "discovered." Unfortunately, in 25,793 BBY. several Tythan scholars began using their knowledge of the Force to pursue power, leading to the beginning of the Force Wars. Peace-minded monks that survived the destruction on Tython established the Jedi Order in 25,783 BBY.Source: starwars.wikia.com