It has a plethora of uses, including but not limited to, protection, banishing, and bringing forth. For many it is a good luck symbol. Members of the Pythagorean Brotherhood wore it as an emblem of physical and mental harmony. It is also equated with the 5 books of Moses and the 5 stones by which David slew Goliath. Whereas the Hexagram, or Seal of Solomon, is known as the Seal of the Macrocosm, the Pentagram is considered the Seal of the Microcosm. Known as the Blazing Star within Freemasonry it appears on the eastern wall of Masonic lodges.
Eliphas Levi portrayed it as symbolic of the spirit's supremacy over the four elements. With 1 point upward it is used to invoke angels and good spirits, while the inverted Pentagram with 2 points upward is used to call forth the powers of evil.
It holds marvelous geometrical properties of the Golden Proportion, the ratio between two measurements so that the smaller relates to the larger in the same ratio as the larger to the sum of both, or Y is to Z as Z is to Y + Z. Phi is the only ratio that meets the definition, 1 to 1.6180339... It is the ratio between the side of a Pentagon and the side of a Pentagram drawn within.
"The Pentagram is a powerful symbol representing the operation of the Eternal Spirit and the Four Elements under the divine Presidency of the letter of the Name Yeheshuah... Traced as a symbol of good, it should be placed with the single point upward, representing the rule of the Divine Spirit. For if thou shouldst write it with the two points upward, it is an evil symbol, affirming the empire of matter over that Divine Spirit which should govern it. See that thou doest it not." (Golden Dawn, Pentagram Ritual)
"There shall be the sign of the Pentagram, the Wheel, the Lion, the Eagle, the Ox, and the Man, and each hath an angle assigned unto it for dominion. Hence ariseth the Supreme Ritual of the Pentagram, according to the angle from which the Pentagram is traced. The circle or Wheel answereth to the all-pervading Spirit: The laborious Ox is the symbol of Earth; the Lion is the vehemence of Fire; the Eagle, the Water flying aloft as with wings when she is vaporized by the force of heat: the Man is the Air, subtle and thoughtful, penetrating hidden things." (Pentagram Ritual)
"The currents leading from Fire to Air and from Earth to Water are those of Spirit... the mediation of the Active and Passive Elements. These two Spirit Pentagrams should precede and close Invokations as the equilibrium of the Elements, and in establishing the harmony of their influence. In closing, these currents are reversed."(Pentagram Ritual)