The left hand has been associated with weakness and subversion for a very long time. The word Left comes from the Anglo-Saxon lyfy which literally means weak. The left hand in some cultures, had always been considered to be the weaker hand, and the right hand was known as stronger one. The Latin word, sinister was related to the use of the word left, and also of evil and this association is still used today. This relation with left and the reversal of the natural order of things, illustrates the meaning behind what the left-hand path represents.
It has been said that the left hand takes in and receives energy and the right hand exudes energy. In the book called The Witches Bible, the authors describe the Gardenarian Wicca method of creating a circle by using a right-facing motion. It is taught that the High Priestess opens the circle using a Sword by moving around the circle in deosil, "from North to North". The movement in reverse, or deosil, is an undoing of actions. When the Priestess closes the circle, it is done with a left hand motion, called Widdershins (counterclockwise). According to them the right-hand action is what creates, and the left-hand action is what destroys.
The associations with left and right, have also been used in divination of events in nature. In ancient Greece, Homer wrote about type of divination using flying birds- the bird that flies to the left represents the bad omen and the bird that flies to the right represents the good. Left and right were common associations with evil and good. So this association with the Left, and unfortunate events, endings or evil has been known for a very long time.
The Left, as weak, sinister, strange or odd has had a long history. Those who associate with the left-hand path find it to be a path of personal empowerment. For some comparisons consider how most right-hand path religions or practices often work for the benefit of a god, while the self is denied for the benefit or healing of others. Within the Left Hand Path, the self is god, or the center of consciousness. It can be said that the left hand path is self serving. In right hand path practices the self is often denied in exchange for association with a higher power.